Of course, it's theirs to do with what they will, but I will always see Revan and the Exile as female. LOL
I just couldn't get into the Bastila romance, and she can be redeemed either way - I have girlfriends who are so intregal to my life I would do anything for them - so even saving Bastila as a female can give me chills. I was terrified of "losing" her.
Carth is older than Revan, but I don't think that matters all that much in times like that and a situation like that - they've both lived through horrible times and you tend to come through that with a sense of what is important - and years may not be it.
The Exile I could more easily see as a male, but again found more interesting as a female (perhaps because there are so few video games with female characters who don't need rescuing by a big male hero - or even a child male hero).