What if two spermatozoide get in to the egg?

Dizygote twinning: Dizygotic twins occur when two separate sperm cells fertilize two different egg cells. This type of twinning is also known as fraternal twinning. Dizygotic twins can be of the same sex or opposite sexes.

Monozygotic twinning: Monozygotic twins occur when a single fertilized egg splits into two separate embryos. This type of twinning is also known as identical twinning. Monozygotic twins are always the same sex.

If two spermatozoa enter the egg, one may fertilize the egg while the other one disintegrates. The fertilized egg will then develop into a single embryo, which will eventually become a baby. In rare cases, both spermatozoa may fertilize the egg, resulting in the formation of two separate embryos. These embryos may develop into two separate babies, or they may fuse together to form a single baby with two heads (or other body parts).