This is an old Sicilian Trick:
Have the mother-to-be lie on her back on the floor.
Take a gold wedding ring, and string it on a heavy gold chain of a necklace (close the clasp)
Hold it like a pendulum about 4-5 inches over the fattest part of the 'baby bump'
Watch it spin.
A circle is a girl
An oblong swing is a boy
Don't be surprised how it will move really fast. Just hold your hand still and watch.
It is always right.
Namaste,
Reiki Doc
P.S. you may need to adjust the position of the ring over the 'bump' to catch the best 'spin'.