The scoop on eagles

[Aiwendil]

Roa_aoife wrote:

Now, I don't have the Sil on hand, but I'm fairly certain that Ungoliath is mentioned as a Maia that turned to darkness, and then became the mother of all spiders.

I don't believe it's explicitly stated that Ungoliant was a Maia - though that's a commonly held opinion, and a perfectly tenable one. In any case, your point stands - it certainly is possible for Maiar to have children that are not Maiar. Look at Melian.