Men who prefer to mate with blond women are subconsciously attempting to mate with younger (and on average, healthier and more fertile) women. And by the way, it’s not a coincidence that blond hair evolved in Scandinavia and northern Europe.

The women in those days concealed their bodies under heavy clothing, so blond hair gave them a way to advertise their youth to men.

For the same reason, men prefer a low waist-to-hip ratio. Guys have always loved women with curves more than the scrawny “waifs” the fashion industry tried to sell us on for a while (a trend that was undoubtedly conceived by gay men).

Women with curvier proportions tend to be healthier and more fertile, and often conceive children at earlier ages because they have larger amounts of essential reproductive hormones.

The male obsession with large breasts might seem to defy evolutionary logic, since a woman’s cup size has nothing to do with her ability to reproduce or lactate.

A Harvard anthropologist came up with the explanation: larger, and hence heavier, breasts sag more conspicuously with age than smaller breasts do.

Therefore, large-but-firm breasts provide a way for men to judge a woman’s age by sight. Back in prehistoric times, this might have been the only clue a guy had as to a female’s reproductive value; people didn’t know their ages, and certainly didn’t carry ID. A man simply relied on a woman’s physical appearance to evaluate whether she was a good potential mate and this pretty much remains true to this day.

Blue eyes are another universal preference shared by men and women. The evolutionary psychologists have some up with a pretty interesting reason for this one. When a person sees something they like, their pupils naturally dilate. (For example, when women see babies, their pupils spontaneously dilate.)

It’s an automatic indicator of interest and attraction. The size of the pupil is easiest to determine in blue eyes; therefore, it’s easiest to determine whether a blue-eyed person is interested in you or not. This makes them attractive to us.

In the modern age of cosmetic surgery, any woman can transform herself into a blonde, blue-eyed bombshell through breast augmentation, liposuction, wigs, hair dye and colored contact lenses. Face-lifts and Botox shots can also help restore a more youthful appearance.

And, it works. It fools a man’s primitive brain. It might be obvious to us on a conscious level when a woman is packing two big bags of silicone in her chest, but our primitive brains don’t know the difference since breast surgery did not exist in the ancestral environment. We’re hardwired to find these features attractive.

So guys, the next time your girlfriend catches you checking out the double D’s on your cocktail waitress, simply tell her, “Honey, I was only subconsciously evaluating her reproductive ability. It’s an evolutionary thing, I can’t help it.”

On second thought, skip that explanation. Better to just sneak a peek when your girl isn’t looking!