Sep 28 2009 This is one of those things I always hear, and a lot of women, like Anna Wintour here, do seem to opt for blond as they get older. I always assumed women go blond in their 40s and 50s because it's the easiest way to cover gray, but I've heard some vague evolutionary biology stuff thrown around, too, where people say that blond = youth. Because babies have lighter hair than adults, generally, blondes read as more fertile and youthful. But I just don't see it. It seems to me that a flattering shade is a lot more effective than just going lighter, and tons of babies are born with beautiful black hair. What do you think? Is there some truth to this, or is it all pseudo-science and no substance?