Why can't hybrid aliens disguise themselves?

I don't like how the hybrids work so far. I really don't like that half aliens have no powers at least none I've seen yet. They should always have powers. We should only have to wait and see if the baby will come out looking alien in which case they would need the disguise or if they look human and need no disguise. But they should always have powers. Maybe a slight chance that the baby would come out looking human with no powers. But a baby with no powers should never have anything but human skin color. And these chances should be the same if the mother is alien and with human abductions.

It's not realistic to me and I like to let my families evolve on their own without having to use a cheat to alter their appearances. Its taking the fun out of having aliens in the game for me.