Mid 90’s I believe.  A couple goes to a jungle in south america, to try to find their son.  I remember a river boat and them searching.  At the end the find some old ruins and see many younger boys living there.  At some point they kill the man and chase the woman.  If I remember the dramatic scene at the end it is raining and she is backed against a tree covered in mud and crying (maybe topless too) and they are grabbing and reaching toward  her like they are worshiping her or wanting her to be their mother.

Thanks in advance!