If the two babies are of different genders, then it’s quite easy to know that they are dizygotic twins. However, it might not be as easy to determine if the two babies are of the same gender.

Fraternal or dizygotic twins develop from two different eggs fertilized by separate sperm; ... Mixed-gender twins are the most common type of fraternals, some 50 percent are boy-girl.

Many of the twins are also different genders. And for many of the twins, this will be the first time in their young lives that they will be apart from their siblings, with whom they share a tight ...

There have been some rare cases where identical twins have been of different sexes. Such cases happen when one twin loses a Y chromosome after the zygote splits. Remember that sex and gender don't ...