Well if you want my opinion. I still think the Fraggles were born like humans or other mamles. I never really thought of it anyother way. The subject of birth has always been taboo beecauseof the nature of it. If you think of it would you really want to see a real Fraggle birth? I would think not, so thinking of that as sort of a mysterey makes it that much more interesting. Instead of having everything explained to you sometimes it's ok to have a bit of mystery it leaves more the to immagination. Instead of having one person's opinion about the story.
And sorry to say I to do think Gobo's parent's or at least one of them for sure are no longer living. I believe Gobo's mother died giving birth to him, and this is going to sound weird but it makes sence if you analise the whose personality of Traveling Matt. I think he is his real father and not his Uncle. I think he had to keep who he really is a secret for the sake of protecting both their lives. Gobo didn't know for years 'till he found out when he had a child of his own who had the same strange mark that always looks odd to him but he didn't really think of it. It was just something that crossed his mind every now and again. Matt, Uncle Gobo, and even Wembley were born into a very secret Royal Society and they are born with a born with very uniqie birthmarks that only appear then a certan spell was cast. Only members of they Royal familey could see it if you didn't know the spell to make it appear. Ever seen any of them with no shirt? If not maybe that's the reason why.