The sad truth is, there are a lot of subjects that we may want to cover on shows like SST and such, but they never will be able to: they took a big risk explaining death in 1983 regarding Mr. Hooper, and were successful, however, for every success, there have also been at least two more failures regarding sensitive issues, like divorce for example, in the infamous "banned" Snuffy and Alice's parents are divorced episode that was never aired, because it upset the children in the test audiences. Lou Berger even said there are many topics they'd like to address, but they wouldn't be able to.
Inclusion of gay lifestyle HAD been attemped on a PBS Kids show before: an episode of the Arthur spin-off Postcards from Buster had Buster meeting a girl with "two mommies", but was never aired nationwide, only once on the PBS affiliate that's involved with the production of a lot of those kids shows (WGBH); and sadly, there are a LOT of fanatic conversative church groups and homeschool groups that have boycotted PBS before for trying to teach tolerance of homosexuality... I know, because that's why we don't have those pledge drives at my local PBS affiliate anymore, because those groups dealt a devestating blow to their pledges, their pledges dropped drastically, and they tried to make up for it by increasing the pledge minimum, but that didn't help... nowadays, they only accept private funding and donations, though I know one of my colleagues has told me he wishes they could do something like that to help support children's programming again (and too, he was instrumental in shaping a lot of the facets of Steve D'Monster's personality).
Evencable children's shows have attempted to have some sort o f gay inclusion and have gotten in trouble for it, like the banned Cow and Chicken episode where Cow joins a motorcycle gang called the Buffalo Gals, composed entirely of huge masculine butch women who randomly bursts into people's homes, and chews on their carpets (wink-wink).
Sadly, homosexuality is not seen by the "public" as being "family-friendly", even Johnny Weir has been on the short end of that stick... the last I've heard, the Archie comics were planning on adding an openly gay character to their cast, not sure if that's worked out for them or not, but then again, I really don't know of anybody (other than Drtooth maybe) who actually reads Archie Comics.