The only way to confirm if a character is LGBQ is if the subject were to come up blatantly or if they were depicted in the act. So therefore when sexual content is involved, it's going to raise the rating.
Do you actually have a game in mind where this sort of thing is casually mentioned (like someone just saying they had two dads) or where a very sexualized straight character was in a game inappropriately rated for kids? Moreover is that just an outlier mistake, or is it a consistent pattern?