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Can a woman give birth to twins with different fathers?


Is it possible for a woman to conceive from two different men and give birth to half-siblings?


Yes, this is possible through something called heteropaternal superfecundation (see below for further explanation).

Of all twin births, 30% are identical and 70% are non-identical (fraternal) twins.

Identical twins result when a zygote (one egg, or ovum, fertilized by one sperm) splits at an early stage to become twins. Because the genetic material is essentially the same, they resemble each other closely.

Typically during ovulation only one ovum is released to be fertilized by one sperm. However, sometimes a woman's ovaries release two ova. Each must be fertilized by a separate sperm cell. If she has intercourse with two different men, the two ova can be fertilized by sperm from different sexual partners. The term for this event is heteropaternal superfecundation (HS): twins who have the same mother, but two different fathers.

This has been proven in paternity suits (in which there will be a bias selecting for possible infidelity) involving fraternal twins, where genetic testing must be done on each child. The frequency of heteropaternal superfecundation in this group was found (in one study) to be 2.4%. As the study's authors state, "Inferences about the frequency of HS in other populations should be drawn with caution."


A search on Google will show you that there have been documented cases where twins had different fathers, including at least one case where a paternity lawsuit follows and the mother admitted to her husband that she had an affair.

There are also cases where twins look very different although they have the same parents. Including cases where one twin looks white and one twin looks black. This can happen when you have one white and one black parent, the children can end up being quite white or quite black and twins can look different. And it can happen if both parents are mixed race; they can have children that are lighter or darker than both parents, and twins can be one lighter and one darker.

Twins looking different by coincidence are much more common than twins with different fathers; as mentioned earlier in cases where there was a paternity lawsuit, only 2.4% turned out to have different fathers. That number will of course depend on the behaviour of people.

One newspaper article http://www.theguardian.com/lifeandstyle/2011/aug/19/my-twins-have-different-fathers describes a case with two days between sex with the two fathers which is more than I thought possible. As an example of dissimilar twins see http://www.babycenter.com/0_strange-but-true-mixed-race-twins-one-black-one-white_10364936.bc showing a family who actually has two sets of twins with one quite light and one quite dark.


Woman Gives Birth To Twins - But They Have Different Fathers

Did you know that a woman can get twins from two different fathers? It's rare, but not impossible. You may look surprised reading this, but you shouldn't be because I have a story that shows how this event actually happened in real life.

Graeme and Simon Berney-Edwards had been married for quite sometime before they decided to add a new member to their family. The two men donated their sperms for in-vitro fertilization (IVF).

What usually happens with IVF fertilization is that the egg is fertilized outside of the body and then transferred to a surrogate to allow the fetus to grow.

Since the men were from England, they would have had to go through a lot of paperwork before the child became legally theirs. Therefore, they made the decision to fly to America and choose a Canadian surrogate mother by the name Meg Stone.

She agreed to carry the fertilized egg and nine months later, the couple was shocked after Meg delivered twins.

As it turns out, two eggs had been fertilized from the sperms of both men. They may be the luckiest same-sex couple on the planet since they get to have two kids with DNA from both parents.

The couple still keeps in touch with Meg and are thankful to her. The two twins, a boy and girl, are called Calder and Alexa.

What do you think of this story? Did it shock you or make you feel something different? Let us know if you enjoyed it and pass this along to your friends and family to see if they've ever heard of something like this before.


Superfecundation or heteroparental superfecundation

Superfecundation or heteroparental superfecundation is the word for twins with separate fathers. Each twin has a separate father. For this to happen, two things have to happen:

  1. You have to ovulate twice (dizygotic). This is actually not so rare and probably happens in more than 1 in 50-100 ovulations.
  2. You have to have sexual intercourse with different men within a couple of days to one week prior to ovulation. That allows two different sperms to fertilize two separate eggs.

Both of these events can happen from having intercourse with separate men on the same day or different days, as sperm can survive for up to 5 days. Multiple ovulations happen in about 1% (or more) of all ovulations, and more often when you take ovulation-inducing medications.

A case of superfecundation was recently reviewed by the New Jersey State Superior Court. It was decided that one man is the father of one of the twins and the other the father of the other twin. Each father was responsible to pay child support for each child. Read more HERE.


One set of twins – two fathers: how common is superfecundation?

C onstance Wu, of Crazy Rich Asians, is in talks to star in a new romcom. Apparently, her character is a bit ditzy – a classic romcom trope. But this ditziness will lead to what I am fairly sure will become a new romcom trope: heteropaternal superfecundation.

“It does sound a bit Mary Poppins,” says Michael Carroll, a reproductive scientist at Manchester Metropolitan University and the father of identical twin boys. He explains that heteropaternal superfecundation occurs when a woman gives birth to twins with different biological fathers. Once you can get past all the polysyllables, the romcom possibilities are endless: mistaken identity, twins who look comically different (see Arnold Schwarzenegger and Danny DeVito in Twins), competing suitors.

Although rare in humans, heteropaternal superfecundation is common in dogs, cats and cows, Carroll explains. “Females will have multiple matings with multiple males and this increases the chance of them producing multiple offspring.” Humans, on the other hand, “are not the best at breeding”. That is one way to look at it. So how does superfecundation with multiple fathers happen at all?

There are two ways through intercourse, according to Jason Kasraie, the chair of the Association of Clinical Embryologists. First, a woman can release two eggs at the same time. Since sperm can survive for a few days in the female reproductive tract, loitering in the corner of the womb and the fallopian tube, it would be possible to have sex with one father-to-be in advance of the egg being released, and another just after ovulation.

In the second scenario, the woman releases two eggs a few days apart but in the same reproductive cycle.

Either way, “It’s extremely uncommon,” Carroll says. “It all adds up to many rarities happening in the same cycle.” A sperm’s journey is arduous at the best of times. To have two successful candidates from two different men in a month when two eggs happen to be released … Well, what are the odds?

Kasraie has found two studies of the incidence of heteropaternal superfecundation, both from the early 1990s. One author claims that one in 400 pairs of fraternal twins (those arising from two eggs) fits the description. The second author puts the figure at one in 13,000 cases of paternity. These sound like best guesses. “They do,” Kasraie agrees. He points out that we cannot know the true number, and research has been scant. Most cases come to light only when paternity is questioned and a DNA test carried out. Apologies if this turns out to be a spoiler.


Mother Gives Birth To Twins With Different Fathers, US

11-month old Dallas-born twins Justin and Jordan have different fathers, a phenomenon known as heteropaternal superfecundation that is so rare there are only a handful of documented cases in the world.

Their parents Mia Washington and her fiancée James Harrison went public with their news last week when they contacted FOX4 to tell their story.

Admitting she was having an affair with another man at the time the twins were conceived, Washington said she was shocked that it had happened to her:

&ldquoI have twins, but they&rsquore by different fathers,&rdquo she told the TV news company.

Washington and Harrison noticed that the twins had different facial features and decided to have a paternity test. They went to Dallas DNA Lab Clear Diagnostics who said they had never seen a result like this before and that there was a 99.999 per cent chance that Justin and Jordan were fathered by different men.

The highly probable result is that Jordan is Harrison&rsquos biological son and Justin&rsquos biological father is the man Washington had an affair with.

Lab Clear Diagnostics&rsquo president Genny Thibodeaux described the news as &ldquovery crazy&rdquo, and &ldquomost people don&rsquot believe it can happen&rdquo.

Dr Chris Dreiling, from the Paediatric Association of Dallas, who has not met the family, told Fox News that a woman can release more than one egg during ovulation, and if she has intercourse with more than one partner at around that time, then sperm from different partners can fertilize each egg:

&ldquoBecause sperm cells take a while to travel and eggs take a while to travel there can be an overlap,&rdquo said Dreiling, explaining that it was a very rare event and likely to be &ldquothe only time that we will ever see this occur in the city of Dallas&rdquo.

Harrison said he will bring up the two boys as his own. He said he has forgiven his fiancée and promised to stay with her.

He said they are taking it day by day, &ldquoit&rsquos going to take time to build that trust like we had&rdquo, he added.

Washington said she felt wary at first, thinking he would try but then give up and leave. But she said that has not happened.

&ldquoJames is a good man he&rsquos a great father and genuinely loves both of the twins,&rdquo said Washington, adding that as far as she was concerned he was the father of both boys because &ldquohe&rsquos the one there every morning when they get up and every night when they go to sleep&rdquo.

Washington said she regrets her mistake and wants other people to know that this can happen.

&ldquoDon&rsquot put yourself in my shoes, because it can hurt and it does hurt, but you still have to go on with life&rdquo. She had this advice for other women:

&ldquoBe careful about starting an affair &ndash look what happened to me. Think hard about the consequences first, because the most bizarre things can happen when you least expect it!&rdquo

Washington said she will tell her sons about their different DNA when they are old enough to understand. She has no plans to tell the other father, although she did say &ldquoif when he is older Justin wants to meet his real dad then that&rsquos his decision&rdquo.

Although rare in humans, heteropaternal superfecundation is more common in other animals such as cats and dogs, a fact that is well known to professional breeders. Some kennel clubs for instance allow the registration of litters to more than one male dog or &ldquosire&rdquo, a phenomenon called &ldquomulti-siring&rdquo, and you can purchase DNA test kits from them for that purpose.

Sources: myFox DALLAS/FORTWORTH, Daily Mail, American Kennel Club.


When pregnancy is caused by more than one father

There are myths about women giving birth to children from two different fathers. A look at genetics today, though, shows that those myths might have originated in truth. It's called superfecundation.

The full term for it is heteropaternal superfecundation. The Greeks probably got the idea from cats and dogs, which can bear litters in which each offspring is from a different father. Dogs, especially, look so dramatically different from breed to breed that a discrepancy in paternity was bound to be noticed. But it wasn't until relatively recently that superfecundation in humans was discovered.

Superfecundation isn't necessarily heteropaternal. Superfecundation is a general term for when two eggs get fertilized in two different, to use the scientific term, "coitions." (I learned a word, today!) Generally, these coitions happen within a space of twenty-four to forty-eight hours. Since most incidents of this happen with the same father, there's no practical way to separate this type of superfecundation from regular fraternal twins. Some physicians consider them the same thing. At times, though, there can be dramatic differences. One woman went in for an ultrasound at two and a half months pregnant only to find out she was really three months pregnant, with one fetus two weeks more developed than the other.

Such an extreme time difference in conception is almost vanishingly rare. Scientists obviously want to know how often superfecundation happens. The only way to test how often superfecundation occurs is performing genetic or blood tests on fraternal twins, and seeing how many have two different fathers. The data varies hugely. One test shows that while there are only about three cases of heteropaternal superfecundation in an overall test database of 39,000 records, but the rate goes way up when the parents of twins are in a paternity suit. About 2.4 percent of tested twins, in those cases, were heteropaternal. Another study suggests heteropaternity among twins in the general population to be as high as one pair in four hundred and estimates that one in twelve sets of fraternal twins are the result of superfecundation, if not superfecundation by two different fathers.

It's interesting to think about exactly how this might cause an evolutionary twist. The traditional view is that males could have offspring with many females at once, but females could only get one genetic mate at a time. With superfecundation, a female has a chance to combine her DNA with many partners as well. Who knows what kind of evolutionary effect that has had on animal, and perhaps human, development?


Strange but true: Twins can have different fathers

We all know that siblings can have different fathers – technically making them half-siblings – but what about twins? Yes, it can happen. In fact, one study estimates that as many as 1 in 400 sets of fraternal twins is "bipaternal."

How is it possible? Simple: Two eggs from the same mother get fertilized by two different fathers – within the same ovulation period.

Okay, maybe not so simple. But if your head is spinning, consider that this happens in certain animal species all the time – with more than two fathers! Our canine friends are a clear example.

"Female dogs ovulate multiple eggs," says Joann Boughman, executive vice president of the American Society of Human Genetics. "And when a dog is in heat, any male dog in the vicinity will attempt to mount her, so each egg could be fertilized by a different father, producing a litter of puppies that don't resemble each other in the slightest."

Humans aren't dogs, of course, and most of the time, women ovulate only one healthy egg per cycle. Fraternal twins occur when women ovulate two healthy eggs and both get fertilized. And every now and then, "superfecundation" happens: Two eggs are ovulated during the same cycle and fertilized at different points within the six-day fertility window, resulting in a bouncing pair of twins.

When we see twins, we may assume that both eggs were fertilized during a single act of intercourse. But it's quite possible for one egg to be fertilized during one act of intercourse, and the other during another. For example, consider a couple that has sex in the morning, followed by another round that evening.

It's only logical, then, that when a woman has sex with more than one man while she's fertile, "heteropaternal superfecundation" can occur. That is, each egg can be fertilized by a different father.

However, if you know twins who look nothing alike, don't assume that they have separate fathers. Like any siblings, twins who have the same father can look completely different from each other. They may even appear to be of different races.


Woman gives birth to twins with different fathers

A New Jersey court has ordered a man to pay child support for just one twin, after DNA tests showed that the second baby had been fathered by someone else.

The extremely rare case arose when the woman, identified only as T.M, applied for public assistance and named her current boyfriend as the father of the twins.

But during her testimony, it emerged that T.M. had slept with a different man the week before she believed the twins were conceived.

The revelation prompted a paternity test, which showed that each man was the father of one of the twins, who are now toddlers.

The original partner, identified as A.S. was ordered to pay child support to one of the children. He must now pay $28 (£18) each week for his daughter.

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This unlikely process, known as heteropaternal superfecundation, occurs when a woman has sexual intercourse with two men during the same menstrual cycle, having released two eggs. One egg is then fertilized by each man.

The ruling, made by Passaic County Judge Sohail Mohammad, is thought to be one of only a handful of similar cases across the United States.


How can women have twins with two different fathers?

WATCH: A New Jersey family recently made headlines after a DNA test showed a set of twins had two fathers. Alana Holland speaks to one of the fathers.

A paternity case out of New Jersey is drawing international attention: a DNA test revealed that a set of twins have different dads, letting one father off the hook for child support payments for the second baby.

Superfecundation twins are rare, and are conceived when a woman has sex with two different men within a small window of time while she’s ovulating. In this case, the mother said in court testimony that she had sex with both men in a span of about a week.

It’s quite the anomaly – Passaic County Superior Court Judge Sohail Mohammed wrote in his opinion that he found only two other court cases nationally.

“This is a case of first impression in New Jersey and only a handful of reported cases exist nationwide,” Mohammed said in his ruling.

The father has to pay $28 per week for his daughter while the other was conceived with another man’s sperm.


Here's How Genetics Help Create A Twin Pregnancy

Before I got pregnant, I worried constantly if I was going to get pregnant with twins because twins run in my family. I worried even more after I started taking fertility drugs. Having one baby was daunting enough, but the idea of being pregnant with two seemed to quadruple my nerves and fear. What would I do with twins in my tiny New York City apartment? Keep one in a drawer? The twins are on my mother's side, but are twins from the mom or the dad?

It turns out that it's not only genetics that matter, but also the type of twins being discussed. In my family, the most recent set of twins was identical, which, according to Stanford University, is a freak occurrence that just happens sometimes when a fertilized egg splits. However, fraternal twins, the type born of two separate fertilized eggs, are genetic. According to Stanford, the likelihood of twins during any particular pregnancy comes from the mother, because, as they put it, "A father’s genes can’t make a woman release two eggs."

If you're the woman who is trying to conceive though, it's not just your mom's genetics that matter. You can inherit the trait from your father. Your partner's sperm may having nothing to do with it, but your father's DNA does, according to Science Mag.

The science of twins is something that was fairly unknown for a long time. Until scientists really became interested in the ins-and-outs of inherited traits and what that might mean for pregnancies, we all just sort of guessed at it. Personally, I'm glad I'm having my children in the epoch of ultrasounds and advanced testing. Can you imagine just 70 or so years ago, going in to deliver your child, pushing that baby out, only to be surprised that a second one is lined up ready to go? Talk about a shock. (I hope you knitted enough booties, Grandma.)

According to Columbia University's Go Ask Alice, "There are certain genes involved in ovulation that induce hyper-ovulation, or the release of multiple eggs. If you have these genes, your chances of fertilizing two different eggs by two different sperm increases, resulting in fraternal twinning." Basically, your ovaries are winning at twinning.

Are twins on the mom's side in all instances? No. According to Science Mag, there are multiple factors at play in the creation of twins. They wrote, "In vitro fertilization, for which demand has surged, is more likely to yield twins. Older women, who are having more children than in the past, are also more likely to release more than one egg, increasing their chances of giving birth to fraternal twins."

Age and genetics are important, but apparently, so is race. According to an article in The New York Times, "Twin births have historically been more common among non-Hispanic black women." Although the reason for this disparity in pregnancies is still unknown.

Twins are tricky. If you're older, if you're getting IVF, if you're a woman and either of your parents have fraternal twins in their family tree, or if you're black, or some combination of these, you're more likely to find yourself doubly pregnant. Even if you have absolutely none of these, there's still a chance. If you're a 24-year-old Norwegian fertile turtle and an only child from a line of only children, you still have a chance of conceiving fraternal twins, noted Stanford University.

As for having identical twins? It's a bit like getting struck by lightning or meeting Lenny Kravitz in an elevator that gets stuck for three hours. Some of us are just lucky.

Check out Romper's new video series, Bearing The Motherload, where disagreeing parents from different sides of an issue sit down with a mediator and talk about how to support (and not judge) each other’s parenting perspectives. New episodes air Mondays on Facebook.