How many sperm cells can fertilize an egg?

Fertilization:

1. When one of the million sperm fuses with an egg, fertilization occurs.
2. It occurs in the fallopian tube's ampullary region.

Sperm cells can fertilize eggs:

1. During fertilization, only one sperm can fertilize an egg at a time.
2. This is because once one of the sperms makes contact with the ovum's zona pellucida, no more sperms can enter the ovum.