WOrks for me!   ;-)

There are vast differences in the biological and temporal "costs" of sex and reproduction for males and females in all but very few species of mammals. Simply put, Mother Nature's design is that females 'pay' maximum, males 'pay' minimum to pass on their genes.

Click here for more info re natural gender differences in the "costs of sex"

"In terms of time and energy, the male expends virtually nothing in sexual contact compared to the female (Trivers 1972; Dewsbury, 1981): a few tens to a few thousand calories per contact, depending on body size, and from as low as 2-3 seconds (the bluewhale) to a few hours (the giant tree sloth) (both figures are time from intromission to ejaculation; we won't count foreplay).(4)

Females, on the other hand, have a far greater physical, physiological and temporal stake in the production of offspring, particularly among the mammals (Trivers 1972). In mammals the female must carry the fetus within her body, nourishing it with her own body tissues. She must withstand the not insubstantial rigors of birth. She must then continue to nourish and protect the offspring until it can support itself, often to puberty. All this can take a lot of time, from weeks to years, and burn millions of calories.(5)

The difference in the amount of time and energy males and females must devote to reproduction leads to a difference in how they regard sex. (Bell, 1980; Calow, 1979; Daly, 1978, 1983; Ghiselin, 1974) This in turn leads to a difference in their reproductive strategies ...

Most males are promiscuous (Bateman 1948; Leakey, 1978).(6) Genetically, it is the most practical course of action. The more females with which a male mates, the greater number of offspring containing his genes are possible. In addition, the cost of sex in terms of time and energy is considerably lower for the male than the female. It is therefore in the male's (and thus the male's genes') best interest for the male to mate with as many females as he can.

In most species, females bear the brunt of the cost of sex in both time and energy: up to millions of calories and years of time. Among mammals, she must not only produce the young, she must rear them to the point of self-sufficiency. Thus, unlike the male, she doesn't have the choice of promiscuity, of creating as many offspring as possible as quickly as possible; she cannot abandon offspring as soon as they are born, or her genes die with the infant (Daly 1983)."

Biologically speaking, men are 'designed' in a way that not only presents problems for hygiene, but makes promiscuity - and therefore spreading of deadly STD's - much more likely. So anything that helps make the experience safer, cleaner, and more pleasurable / satisfying for her - (and ultimately for him, too) - is well worth the aggravation imo.

Quite possibly, the traditional 'sacrifice' made by men via circumcision (which does, imo, parallel in a very small way the physical sacrifices demanded of women simply through their biology) - was an important step forward in the social/sexual evolution of this species.