Two Genes May Raise Odds For Fraternal Twin Pregnancies, Vrije Universiteit In Amsterdam Study
Although it's long been known that fraternal twins run in families, researchers say they've just pinpointed two genes that seem to be associated with having such twins.
Fraternal twins occur when two separate eggs are fertilized with two separate sperm, creating two genetically unique children in the same pregnancy.
One gene variant -- called FSHB -- increased the odds of having twins by 18 percent, according to the study.
Fraternal twins occur when two separate eggs are fertilized with two separate sperm, creating two genetically unique children in the same pregnancy.
One gene variant -- called FSHB -- increased the odds of having twins by 18 percent, according to the study.