There may be a couple of explanations if that is true:
Young females were gay to begin with and because of the increased acceptance followed their "hearts"
Young Females in their quest for male attention may act that way for show only.
I definatelly agree on the for show reason, I don't believe people are born gay however (except for a very small majority) and they are "exploring" because they give into temptation.
I also have a theory that the decline in "real" men and the increase in metrosexuality is making women say "why have a man that acts like a girl when I can have a much more beautiful woman"