Sometimes I go into Create-A-Sim (or character creation, in other games) with a particular ethnicity in mind, and sometimes I don't. If I do, it's generally just because I already have a name picked out that pushes me in that direction. A girl named Abrihet will always be black, while a guy named Sven will always be white, for example.
When I first created the Beefs in Sims 3, I didn't go in with an idea of what they'd look like; I basically let the Random button decide that for me. It gave me a white father and a black mother, and I thought, "Cool; I'll roll with that." Then it just took a little more work to make the kids look enough like their mother to suit my tastes, because these games don't really do that whole dominant/recessive traits thing.
When I recreated them in Sims 4, I wanted to make them look similar to their earlier versions. So, this time I did specifically choose to make them an interracial family.
I'm technically bi-racial, myself, although you might not know it from looking at me, because I'm a bit on the pasty side. I'm 5/16 American Indian, though, a mix of Cherokee and Blackfoot. My grandpa made sure I had an appreciation for that part of my ancestry, too; he was a historian of some note who sometimes gave presentations at local schools, and also took me to a few powwows when I was a kid. I've also made the effort to learn a little bit of the Cherokee language.
So, as far as race goes, I'm of the view that ethnicity affects how you look, and culture will have an effect on some of your views and mannerisms, but when you get right down to it we're all just people trying our best to make our way in the world.
As far as sexuality goes, well, I only really make straight, cis-gender characters. It's nothing against anyone who's "other"; that's just the way my instincts run. When I've tried making gay characters in the past, it's just felt forced and not fun to me. I can appreciate other people's gay characters just fine, though; I really liked Peter* from Six Feet Under, and I like Ian from Shameless. Those are characters who get pretty explicit in their gayness, too, so I'm pretty sure it's not homophobia. But my men like women and my women like men.
Later edit: *-I'm sorry; his name is David, not Peter. It's been a while since I watched that show.
