And egg. Sperm and Egg. Why does everyone think they're the sperm? They are a combination of sperm and egg
I prefer to put a positive spin on things. Remember: if you can't be a good lesson, you can at least be a horrible warning!
Also it is currently believed that while only one sperm-head enters the egg, around 100 are needed to soften the egg-"skin" in order for one to penetrate it.
So technically one single sperm is not enough, only the genetics of one sperm (assuming the egg as a constant).