How does fertilization create genetically unique kids from the same two parents​

First the ovulation happened in the female's reproductive organ. The egg meet the sperm in uterus (Here, a lot of sperm will swimming to be the first one who get into the egg) the sperm has some enzyme in their head that make them can get into the egg (the egg contains jelly).

Once a sperm get in the tail will break and the nucleous from the sperm and the nucleous from the egg meet.

This is the fertilization process after ovulation