What Are Heteropaternal Superfecundation Twins?
Heteropaternal superfecundation twins occur when a woman releases two eggs during the same ovulation cycle and each egg is fertilized by sperm from different men. The result is fraternal twins who share the same mother but have different biological fathers.
How Rare Are Heteropaternal Superfecundation Twins?
Heteropaternal superfecundation is rare in humans but documented in several confirmed cases. Most twins are either identical or fraternal with the same father. When fraternal twins have different fathers, it is usually discovered through genetic testing after birth.
How Is Heteropaternal Superfecundation Confirmed?
Doctors confirm heteropaternal superfecundation with DNA paternity tests comparing each twin to potential fathers. Genetic differences between the twins show they cannot share the same biological father. In some cases, this discovery has affected legal questions about child support and custody.
Why Does Heteropaternal Superfecundation Occur?
For heteropaternal superfecundation to happen, a woman must ovulate twice in the same cycle and have intercourse with two different men within a short timeframe. Sperm can survive inside the female reproductive tract long enough to fertilize both eggs. Learn more about twin conception at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3176030/
