This is a posterior view of the caudal region of the male pig. Note the single anal opening and the lack of a urogenital papilla (compare to female).
Note the swelling just ventral to the anus. You may or may not find these swellings on your fetal pig. They are the developing scrotal sacs and contain the testes.
But what if it's a female? If you haven't done so already, click here to see It's a female.