What are you talking about? Barbie has had a boyfriend since forever. Fairy Tales read to children as young as one year old are rife with princes rescuing princesses, getting married and living happily ever after. We start introducing amorous relationships to children almost as soon as they're able to understand language...maybe before. This is the case in toys, books, cartoons, pretty much across the board.
I think you missed a big point in that a lot of those stories were designed long before it was "ok" to be gay in the U.S. and while a lot of the core characters haven't changed (Barbie is still with Ken ect) a lot of those lines and dolls introduced since then don't "have" anybody in particular to be with so you just kinda fill in the blanks with the kid's imagination. Buy two Kens or two Barbies and make them a couple, even. Who says you can't? Is there a show where it shows Ken w Barbie? (I really dunno). The dolls don't even come in hetero pairs usually (although that's more due to them wanting to charge more for two dolls I guess). That's like Cabbage Patch and Build a Bear and even more defined characters like Spongebob and MLP and Sesame Street and Pokemon stuff, they don't make romance a focal point on a regular basis to the point where for a lot of main/recurring characters you just don't know who/what they are into, so you fill in the blanks yourself (or the fandom does, lol)
There are a lot of stereotypes with a lot of toys that you can go into detail on but the dolls and toys are NOT about having sex and making babies, at least not on a regular basis (I know I've seen prego dolls before but yea, not common...)., part of being in Amurica and the Puritan background ect. that's why most don't have have vaginas and penises. There's tons n tons that are simply there and you fill in the blanks on everything about them (except, as you mentioned, ones based on old-school fairy tale stuff, those are about very certain people and thus not supposed to represent the kid playing with them. Kinda why I have more of a problemo with this game because it's made to represent "you" and that's a core theme of it)
I'd like some more stories about adult characters and cartoon made characters that are
specifically gay/lesb/bi/trans and so on, yea, but that's not the same thing or what i was discussing.