Fruit Fly Sperms Make Famales Do Housework After Sex
This definitely cannot be used in middle and high school classrooms, but it's just something funny I saw and thought it was cool. The sperm of the male fruit flies are attached with sex peptides to the tail of the sperm, which after sex, inhibits the females to get any rest and forces her into intense activities.
Now we have an idea of where men get their genes from. =)