Can an egg cell be fertilized by 2 different sperm cells?

Answer

An egg can be fertilized by two sperm. In this way, the egg cell gets an extra set of 23 chromosomes. A normal fertilized egg has 46 chromosomes. An egg cell that has been fertilized by two sperm cells has 69 chromosomes. We call this triploidy, referring to three (tri-)sets of 23 chromosomes. An oocyte with triploidy will not be able to develop into a viable embryo or fetus and will therefore die resulting in a miscarriage for the pregnant woman.