I asked him about it:
'The option to choose a male prostitute at Big Jim's place should always appear, regardless. Choosing this option will always result in Adamo the tailor shortly thereafter trying his luck (i.e. it's taken as a pretty good indicator that the player may wish to play a gay character).
However, I didn't want to have to force the player into intimacy with a prostitute just to prompt Adamo into making his move, but neither did I want Adamo to always try his luck regardless - he's much too clever and cautious to behave that way. It suits (no pun intended!) him better to have more of a 'sixth sense' about these things, so the earlier choice of "More caring, more charitable..." will also prompt Adamo to try his luck, regardless of the choice made at the brothel.
Moreover, by this means it's also possible for a character to indicate bisexuality, by choosing a female prostitute at the brothel while also being open to Adamo's advances as a result of the earlier "More caring..." option.
I know it's far from ideal for various reasons, but for some reason it annoys me when a Choice Game simply asks me outright: "Do you prefer men, women, or both?" I feel that as game designers we should be able to make that determination (and ones like it) based on rather less direct choices, as part of the actual story.'