When you consider how babies are made, you bump up against a basic math problem. No need for calculus here, or even the mental gymnastics of carrying the one. It鈥檚 a problem of doubling.
Black, white, and orange 鈥 the signature colours of a calico cat. Subtract the white and you鈥檝e got tortoise shell colouring. But there is gender colour discrimination at play: calico and tortoise...
There is a common parental misunderstanding that arises when the term 鈥渋dentical twins鈥 is paraded around. Identical twins are known scientifically as 鈥渕onozygotic twins.鈥 This Scrabble winner of a...