Isn't this Wiki about the Disney Big Hero 6, and not the Big Hero 6 from Marvel? User:Mighty Mega Man has been creating articles that apply to both versions. This Wiki to me seems more focused on Disney's BH6.
Who said it was indecent? Neither is actually worse than the other. Gender is social, but sex is biological - saying it isn't an offense. Other PG-rated wikis also apply "sex" into infoboxes and no eyebrows are raised. If you're thinking of its other meaning, then that doesn't need to be brought up.