They have the luxury of choosing a mate because it is a she, as opposed to choosing a mate that will support him and stick around after the child is born. It would seem plausible that it would be an incredible payoff for ancestral males to have a relatively fast and frequent sexual arousal, allowing for the copulation with potentially many women. The data shown here suggests that males and females have sexually differentiated systems. Some social scientists claim that sex differences are a result of sex guilt, or rather erotophobia-erotophilia. Going reaching farther into why men are more attracted to the physical qualities of a woman than that of a woman, it was found that the androgen levels might be the physical component to these differences in men and women.
Men tend to lust and have an appetitive desire.
This can be seen in male sexual fantasies as well as pornography. Because men lust, their fantasies often de-personalize the women to a sex object and therefor usually focus more on the sex organs, sexual acts, and the physical attributes of the woman. Men tend to become more sexually aroused by visual stimulation therefor making the fantasy more likely to focus on the visual images of the imagined partner. Men also tend to view women as the sexual object and often see themselves performing the act to the woman. Male fantasies also reflect physical attraction in that they are more likely to have more than one partner in the fantasy.