In rare cases, fraternal twins can be born from two different fathers in a phenomenon called heteropaternal superfecundation. Although uncommon, rare cases have been documented where a woman is pregnant by two different men at the same time.

How rare are twins with different fathers?

One study found that twins with different fathers occurred in 2.4% of all fraternal twins whose parents had been involved in a paternity lawsuit. Even though 2.4% might seem like a high percentage, this study only researched a small number of pregnancies.

Can two sperms enter an egg?

In this case of semi-identical, or sesquizygotic, twins, the egg is thought to have been fertilised simultaneously by two sperm before it divided. If one egg is fertilised by two sperm, it results in three sets of chromosomes, rather than the standard two - one from the mother and two from the father.

Can triplets have different fathers?

The Times said the phenomenon of twins or triplets having different fathers can occur when a woman, having ovulated at least twice in the same cycle, sleeps with more than one man within 24 hours and conceives children by them. The children, one of whom died after an illness in 2001, are now 10.

Is it safe to have sperm in you while pregnant?

Sperm is typically considered safe for pregnant women and babies. That said, check with your doctor if you have any questions about the overall safety of sex due to any risk factors associated with your pregnancy.