Actually, while the story indicates one is the son of the other, we don't even know who these two characters are according to the "First Vision" account. (They are both simply two unnamed "personages"--Personage #1; and Personage #2)...and when you look at a handwritten account by Smith of this "First Vision"...there is no second Personage. (I guess in that version, one of the two "Personages" was superfluous)
The Father got his body when he was a Man, just like us, on another planet where he learned to be a god by slowing growing in obedience to the laws and ordinances of the gospel on the planet where he was born.
Well, just imagine that. God having genes from his mom. Imagine that, the God of gods being reduced to some twinkle in his mom's eye way back then--and that at one point, that's all he was.
He's holding his head in the picture. Maybe somebody hit him on the head right before this vision and he was seeing double.