junerune

Aliens that look like humans visit earth and pose as friendly visitors, but have an ulterior motive. A girl has sex with a male Alien. She gets pregnant and fears that her baby will become a monster. When her baby is born, it comes out normal, but she realizes that she has twins and the second baby really is a monster. At the end of the movie, I think a virus on earth kills off the alien race, making them leave earth. The virus doesn't affect humans...

I think this is the movie V, or the miniseries V. I watched this when I was a little girl, so I am not sure... Thanks for your help.
Also, I do not know if I am actually describing 2 movies or just 1... I know it was in the 80s.

LilyRT

you're describing both V the movie and V the final battle--2 movies.

http://www.imdb.com/title/tt0085106/
http://www.imdb.com/title/tt0086823/

there was a TV series that takes place after those movies.

they're remaking the original movie and coming out with a new sequel (at least, the original author is trying to find someone to fund a new sequel)