My sims got abducted but didn't get pregnant, BUT I'd saved just as he was abducted and so kept going back on the save and after three tries he was pregnant. Now the alien child is married, even though his beloved found out he was an alien. They had a child, but he doesn't seem to be a hybrid. Definitely using the satellite dish and searching for truth did it got the abduction thing going on and he was in the science career.
The save and reload method @Gednaa suggests is awesomesauce and highly effective. I've used it in several saves to get Snagglefluster. 😉
