People are often exact duplicates of remote ancestors, or of their parent at the same age.
At least one of a pair of identical twins is born evil.
Radiation causes mutation not to your future children, but to you, there and then. Mutation is never immediately fatal, but first either makes you into a formless blob, or a functional creature with animal-like features.
Interbreeding is genetically possible with any person or creature from anywhere in the universe.
Newborn babies can babble, crawl, and hold their heads steady.
On to Bodily Functions.
Back to Binoculars/Glasses.
Back to Movie Cliches.