Those are, of course, the lucky ones, though the college girl stripper/hooker/performance artists, not the streetwalkers and we haven't even looked overseas, where poor young women may have fewer choices.
Is it ever ethical to pay such a "professional"? Many would say of course not. Others, including myself in some moods, would choose the practical over the ideal and point out that while such transactions may be distasteful, if nobody pays her she will starve, or be beaten, or both. This is one of those situations that has no perfect answer, the world in which it occurs being too imperfect to yield one.
I don't think hiring a street prostitute in a poor country is really your cup of weak yak-butter tea anyway. A better idea, in your position, would be to cultivate a few pseudo-intimate online relationships and save your money for the occasional trip abroad to visit one of those (provided you've netted an actual woman) or, failing that, to pay a fancy freelancer a lot of euros.
Andrea is home with the kids and going stir-crazy. Write her a letter! Ask her a question! Send her your tedious e-mail forwards! On second thought, don't do that. Just ask her a question.
Andrea is also teaching two classes: "You've Really Got Your Hands Full" a realistic look at having twins at Birthways in Berkeley.