Our response to the things that scare us, from threatening men on dark streets to hairy spiders in the bath, is programmed to become active at different times in our lives, suggest two studies on the genetics of fear

Scientists already know that fears and phobias are shaped in part by genes.

But less is known about when the genes involved act and what effect they have.

his suggests babies are born with a "mental template" for spider shapes, and potentially for other things that may harm them

Once identified, spiders produce fear and disgust in many people. But that reaction, and the genes that shape it, change during our youth, according to a separate study by Kenneth Kendler of Virginia Commonwealth University in Richmond and colleagues.