A Cancer Moon doesn't mean effeminate and yes, that is far too simplistic, though Cancer and the Moon are considered somewhat feminine. Would you describe Keanu Reeves effeminate?
I'd actually be looking for more Libra, Pisces, maybe even Leo placements (no, Leo's not usually considered feminine, but I think a strong Leo can be more sexually unrestrained, all the fixed signs actually). I find that Venus, while arguably the most feminine planet of all (psychologically speaking, not the female/mother archetype most say the Moon is supposed to be) works the opposite way in a male chart and if angular or combust and makes him more consciously unfeminine, yet if her sign and exaltation are strong (Libra and Pisces) the feminine aspect of his personality still shines through, also if Venus positively aspects the ascendant.
I think If we're talking about a person's sexuality we must also look at the 8th house, Pluto, whatever aspects Venus makes and the condition of the rulers of the 5th, 7th, 1st and 8th house. Vesta is also supposed to be related to sexual issues and Chiron of course is psychological healing and issues and stuff like that. Some people would say Mars too, but I think Mars is more about action first, then sex and lust later.