The process of conception is more than just the meeting of the egg and sperm — it is an actual battle!
The egg is a fortress, which is not easy to get into. It is surrounded by a thick outer shell. There is a misconception that the fastest sperm fertilizes the egg. Actually, no sperm can do it alone. A few thousand of the most agile and strong candidates try to reach the egg. Each of them has a vacuole at its head filled with special enzymes that break down the outer shell of the egg, and they all begin to work on overcoming this barrier. The winner is not necessarily the strongest. Rather, it is the luckiest, the one who is closer to the entrance created through the joint effort of all.
When conception happens, the genetic material of two germ cells fuse together in the course of 24 hours.