In defense of Robin: She gets a bad rap by some fans
Some fans like to bag on her saying she's "the most annoying character" blah blah blah, but I truly think most of you who say this are MISSING THE POINT of her character. She is SUPPOSED to be this way. In fact, her behavior as a somewhat spacey, hormore-driven teenager is one of the most important driving points of the entire plot. Everything the character does and experiences is critical to the progression of the story.
And NO (repeated from another post), she DIDN'T get a lot of people killed by leaving the safe house. All she did was follow some sunlight through a crack in the wall outside (a metaphor for her budding adulthood and sexuality). It wasn't smart but it was a kid being a kid. Actually her FATHER got a lot of people killed by giving up secrets to the Visitors in order to save her after she got caught. He sold out the human race for his family. Robin was just a typical Valley-Girl high school kid caught up in unfathomable circumstances. I don't even think the girl had a drivers license yet. That's part of the appeal of her entire character - that all this crazy sh** is going on around her but she's still a teenager with raging hormones and a crush and she doesn't really "get" what all the adults are doing or talking about when it comes to the aliens. Not every teenager in Nazi Germany was Anne Frank. Many were oblivious and "status quo" and worried more about their day-to-day. They went to school and talked about boys and dreamed about their futures. Adults, too. That's Robin.
I was roughly Robin's age when this movie first aired and her character seemed like many girls I went to high school with. Also part of her involvement in the plot (and the Bryan crush) was to draw in teenage viewers - which worked.
As for having sex with the young alien Visitor (and getting impregnated)... That doesn't make her a whore. She was a very inexperienced VIRGIN for crying out loud. She was being held captive on a terrifying spaceship high above earth, not knowing if she'd ever see her family again, or if her captors might release her or torture or kill her. She was scared and easily manipulated. She wasn't all LAHDEE-DAH I'VE BEEN KIDNAPPED AND I'M GONNA GET MY SEX ON WITH MY CRUSH!!!!! You can plainly see she is a mess of emotions when Diana orders Bryan to go in and do the deed. And in he walks, this beacon of trust and protection who lies to her. And the plot device touched on a lot of interesting concepts of the times - teen sex and teen pregnancy (and later, abortion).
(and I'm not even getting into the importance of her "testing" the Red Dust on Bryan which basically sets the stage for humanity to make the planet undesirable to humans)
The Valley-girl speak and teenage decisions are programmed to sound dumb and irritating to adults. She's a brilliantly written character who is absolutely integral to the advancement of the entire plot. Every character in a story either exists to advance the plot or serves as mainly filler. Robin advanced the plot as much as if not more so almost any other character in the story.