Beyonce's Fetus -- If I Were a Boy ...

It's a little creepy ... but THIS is how Beyonce and Jay Z's kid might look ... if it's a boy -- at least according to one famous forensic artist.

Dr. D'Lynn Waldron -- who's worked as a consultant for the FBI -- has just released a new digital image ... showing how she thinks the kid will look ... after he's old enough to pop his own collar.

Waldron believes the kid will have his "father's features, mother's eyes."

No pressure, kid.