See.. what gets me is a lot of people see gay or sexual orientation and immediately think about sex... Sorry but being gay is not all about sex. Not anymore than being straight is. No, kids shows are not the place to be talking about sex.. but what's wrong with one of the characters having two moms instead of a mom and a dad? Just don't make a fuss about it, but show non-heterosexual couples do exist and they are not all strange and freaky.
In older kids shows when you've got the subtle flirting stuff going on between characters, it is always between a boy and a girl... why not two boys or two girls? Or heck, a love triangle with one of each? Why not introduce a character who's in mid transgender transition? Sadly media, especially media for children, is still stuck in the hetero-normative and cisgender-normative mindset. There's nothing wrong with showing the majority of people being straight or cisgender.. that's the way life is. But there are a lot of LGBT people out there too.. Ignoring that they exist, or worse using negative stereotypes when they are shown isn't very realistic and hurts those who are LGBT, since all they see are examples of what is 'normal', ie, straight and gender-conforming.
Of course, if gay or trans character would show up in children's media then the fundamentalist conservative crowd would be up in arms about 'corrupting and brainwashing the youth with their perverted agenda'. Despite the fact that you know... the entire history of media has been mostly pushing being straight and gender conforming as 'normal'... In other words, they think the only influencing agenda that should be shown is the one they believe in.