A bundle of joy? More like a bundle of shock as a mother discovered that her twins are actually half-brothers with different biological dads.
In a report by Brazilian news outlet Globo, the 19-year-old woman had a sexual tryst with two men on the same day before giving birth to twins nine months later.
According to her, her suspicions regarding the babies' father started to surface when they were eight months old, so she took a paternity test from one of the men to ease her doubts. However, when the results came, it was found that the man was the biological father of only one of the babies.
Because of this, she called the other man she had sex with and told him to take a DNA test, which came back positive.
"I was surprised by the results. I didn't know this could happen. They are very similar," the woman, who preferred not to be identified, told Globo.
The incident is certainly something out of a fictional story. However, the woman’s attending physician Dr. Tulio Jorge Franco said that pregnancies such as this are called "heteropaternal superfecundation"—something extremely rare, but not impossible.
"This pregnancy happens when two eggs from the same woman are fertilized by different men. In this case, the genetic material of the parents is different and the eggs of the mother are also different. The babies develop together in the same pregnancy, but each one in its own placenta," Franco explained to Globo.
Heteroparental superfecundation can happen even on different days because sperm cells can survive for up to five days, according to Obstetrics and Gynecology professor Amos Grunebaum on his reproductive health website babyMed.
Franco said that this is not the first case of this happening and the woman's case is actually the 20th one recorded in the world.