If identical twins marry identical twins...

What happens, genetically, when a black and a white human partner have children? And if a pair of genetically identical twins marries another pair of identical twins, are their kids genetically brothers and sisters? Do birds have ears? And if you lose one of your special senses, do other senses strengthen to compensate? What's the reason for human handedness? And does a blood transfusion recipient carry the genes of the blood donor? Dr Chris has the answers... Like this podcast? Please help us by supporting the Naked Scientists