is Apollo really gay? and if so, how in the world does he have kids in the Apollo cabin?!

Apollo is a deity from Ancient Greece and the Ancient Greeks cared very little for differences in gender when it came to their sexuality. más than likely all the Gods and probably a lot of the Demigods have leanings towards both genders. The most accurate way to describe his sexuality would be Pansexual.

Because he's bi-sexual. A LOT of Greek gods are, do any amount of digging and you'll see that.

because he is bi-sexual

Apollo is most likely bi o pan-sexual. Just because he liked a guy doesn't necessarily mean that he won't like women.

He's probably pan.

What makes tu think he is even gay?