American Pharoah -- His Semen's Worth a FORTUNE ... Says Bob Baffert

Everybody wants to bang a winner ... which is why the price to make a baby with American Pharoah just exploded into the 6-figure range ... so says his legendary trainer Bob Baffert.

With Pharoah's father already getting around $60k-a-pop to procreate ... we had to ask Baffert how much cash Pharoah's swimmers will fetch when he gets put out to stud in February.

Baffert says AP will make a fortune ... but nowhere close to the #1 horse inseminator on the planet, Tapit -- who's pullin' in roughly $300,000 per session.