Does knowing that someone has a large penis make them more attractive?

My female friend and I were having this discussion about penis size. I had just read a study saying that men who were endowed (7.1+ inches) had more sexual partners per year (7.6) than average guys (3.6). I said it was amazing that I had ever been with a girl seeing how shy I am. She said maybe it's because I always show girls pictures of my penis... so here is my question: If you are slightly attracted to a guy and you find out how big his penis is does it make more/less attracted to him depending on his size? I guess a second part to this question would be this: If you weren't all that physically attracted to a guy could knowing the size of his penis make you more attracted to him?