I watched BREEDERS, interesting movie but no it. I remember the movie I saw being post apocalyptic in some way. I think one of the girls was raped over a rock in the desert
You definitely need to check "The Terror Within" and "The Terror Within 2" as was suggested by LilCerberus. What you described made me immediately think of those two films. Then I noticed that LilCerberus already thought of them.
Onother Possibility, could be The Terror Within 2
The series outline fits what you described, involing lizard men in the desert attacking scientists in an underground laboratory, & I specificly recall a scene in part 2 in which the scientists are running a simulation of the insemination process on a computer tha sounds kinda' like what you described
Corman & his freudian misogyny/misogynic freudianism
Gotta love it