Idk. I have friend that do though. It gets kinda strange for them as a couple like idk how to explain. Also maybe just add a simple no instead of that rude "No! it will be too weird" you put up.
Don't have a problem with trans people (and I hate to reduce another conversation about trans people to this) but it would really depend on the genital situation, at least for me. Like if it works for them and/or their partner then by all means that's great, but I'm not sure I could personally have sex with someone who's downstairs isn't fully formed, is still of the opposite gender and/or is too small, etc.
I used to eat ***** in college and during some "swinger" phases with my husband but I can confidently say that's out of my system. If i'm gonna d8 someone, there needs to be sexual chemistry if things are going to go anywhere serious, and if you don't have a dick we ain't gonna click. Scissoring or whatever is simply not enough.