"Men...70% are all stupid nowadays."

Two science teachers, one male, one female, were debating whether intelligence is inherited from the mother or the father. Because I thought they were joking, I said, "The mother, of course."

But they weren't joking. The discussion began including talk of chromosomes and recessive traits.
 "If the child is stupid, does that make it the fault of the mother?"
"Yes, it would be due to the mother, but remember there are some genes that remain hidden. The mother could be carrying the genes even though she would not express the trait."

Surprisingly, it was the male teacher who concluded the debate with the statement, "Men...70% are all stupid nowadays."