I don’t need to explain why the option to have a non-white, non-male, non-straight person as the main character of a blockbuster action science fiction story is important
This highlights an interesting current even in mainstream culture - safe depictions of homosexuality. Pretty much it's fine... as long as the homosexuals in question are lesbians... and they have smoking hot bodies. There are 12 romance options combined in both games. Four of them are for either gender protagonist. One is a human woman. Three are of a race with only one gender, that happens to look like human women. If you play with a male main character, you won't be exposed to the slightest homosexual visual, even if you really want it.
http://masseffect.wikia.com/wiki/Romance
It brings in another interesting effect - wildly different races are wildly different, crazy body types and so forth... as long as you're male. If you're female... well... you get to look like a human female. Every turtle-man alien we see is just that, a man. They have females, but we never get to see one. Same thing happens in World of Warcraft - the male character models are really different, but females all have similar body shapes.