Do some girls turn gay or bisexual from being hurt by a guy?

Actually, i beg to differ.
One of my best friends chose to "play for the other field" after being hurt too many times by guys. Sometimes it takes a few heartbreaks to realize that you actually need someone that can understand the way you think, and with girls who could possibly know you better than another girl?
Milicent does have a point though, it's the big thing in school to be bisexual or gay just for attention, and you can usually pick out those people that aren't 100 percent real. But there are those who are actually gay and are proud to admit it, though some obusively claim that they too are only out for attention.
In answer to your question, i say yes, some girls do choose to change their sexuality due to hurtful men in their lives

There seems to be a lot of "koolness" attached to bisexuality these days and too many young people are jumping on the bandwagon,before we know it being straight will be perverted! To answer your question NO.

I agree with Tara, for the main point. Some girls, it's true, keep on being straight after heartbreak, and some girls pretend to be gay for attention. But I know many people who have turned gay, after just completely giving up on guys, having been hurt by them one too many times.

(Check out the link on my profile! It's an awesome site!)

No, sexual orientation is about the gender of the people you are sexually attracted too.  It is possible that you may choose not to be in a relationship or to not stay in a relationship long because you have been hurt many times.

Being bisexual isn't easy.  They aren't accepted by the straight community.  Nor are they always accepted by the gay community because they can have straight relationships.