Heteropaternal Superfecundation might sound like something scary, and even contagious, but it’s actually an amazing event that is more common than people realize. Superfecundation is when two or more eggs in the same cycle are fertilized by sperm from different men. Heteropaternal superfecundation is when fraternal twins have different fathers.

How is it possible?

A woman is usually fertile about two weeks before her menstrual cycle begins and for the five days immediately before it begins. If she has sex with multiple partners during this period, it is possible for sperm from different partners to fertilize different eggs in the same cycle, resulting in fraternal twins. Many people don’t know that sperm can remain alive for up to 5 days!

What does it mean for the fathers?

Fathers who do not live with the mothers of their children are usually tasked with paying child support. In a recent case in New Jersey, a court ruled that a father being sued for child support for twins was actually only the biological father to one of the twins, and so only had to pay support for that one child. Ultimately, in the case of twins—especially fraternal twins, or twins who do not look alike—this means that fathers should give consideration to paternity tests to reliably establish the likelihood of paternity for both children.

What does it mean for the twins?

Twins with different fathers are still siblings. They still share the same mother. Although it may complicate some aspects of paternal relationship, that bond between those twins is likely to remain the same. It is up to the families to decide if they need counseling and what sort of relationship the twins will each have with their fathers. It also means that twins can be born that are not only of different sexes and appearance, but even different racial makeups.

Don’t jump to conclusions

Of course, it’s important to remember that just because twins don’t look alike, that doesn’t mean that they have different fathers. Twins can come from the same father while still differing in appearance. Fraternal twins are also possible with gay couples who both donate sperm to a surrogate. It’s important not to jump to conclusions every time you see a set of fraternal twins. Heteropaternal Superfecundation shows up about once in every 13,000 paternity cases. Contact HomePaternity for more information regarding paternity testing.