That too, is a legit question. And it's cool to ask.Well, it is true that there would be genetic issues with them having a kid, but actually it's not impossible. If you are really in myths about dragons and do your research:someone mentioned that dragons can actually mate with anything. So that applies to equines too. And as for what there kids would be like, there probably would be some issues. I think a good example of a sparity child would be: [link] . In it, they mention that a hybrid called a kirin/qilin: [link] exists, that is part unicorn, dragon (During the Jin Dynasty, the Qilin is depicted as wreathed in flame and smoke, with a dragon-like head, scales, and the body of a powerful hooved beast such as a horse), and overtime became its own species. Though one issue they created was that he was sterile, had weak magic, and would get vestigial wings.Now as for maturity and age, this one's difficult to really say, since most age in the show is left vague. For many sparity fans, they tend to say that in dragon years, spike is still quite young, but in pony years he's only a few years younger than twilight, making it less awkward for rarity and him to date. As for maturity, in all honesty it really depends on the episode. Episodes like Lesson Zero, Magical Mystery Cure, The Secret of my Excess, show that he can keep a level head in bad situations, and keep his friend from going insane, and himself from doing the same. But then episodes like Spike at your service, show that he's still quite young and does brash decisions (though to be fair, twilight wasn't paying attention, and inadvertently told him to be with her, when he asked). I'm sure though, seeing how much he loves her, and how much he takes his love for her seriously, he would be the more "head on his shoulders" spike in the situation. Plus I'm sure that some ponies would judge rarity, but I'm sure that if she really loved him, she wouldn't care. Plus spike does know some high society ponies like Hoity Toity, and y'know the princess. So he isn't an outcast. Plus ponyville likes him just fine as an equal and a friend.I hope this made you understand more about the ship, and how at least a few see it. So it's not entirely impossible for this ship to happen (though they may not outwardly say it in the show they may hint at it). And humanizing it, some people take a sort of "Dragon ball" approach to spike. Sorta like how goku looks human, he's alien and is actually part monkey. Spike would look human but be part dragon (including the tail).Yeah, I think I'll go do that too.