i don't think that's true at all. some redheads are gorgeous, yes, but most of my guy friends complain about them not having visible eyebrows and eyelashes. when guys hang posters of girls on their walls, are they usually red heads? nope. I hang out with red-headed girls and they don't seem to get very much male attention at all infact.
i think the girls that dye their hair red, or naturally have darker red, auburn hair are the more attractive ones to guys because they have more appealing coloring than the girls with bright orange hair and have white eyelashes and eyebrows (not saying that they can't be pretty either).
Apparently guys do in fact find redheads most attractive..probably something psychological. Or perhaps its because there aren't many redheads as the gene for red hair isn't very common so they stand out. FYI, guys are most attracted to the color red in general, they like red clothes on women etc. One psych experiment asked guys whether they liked the same girl in red or blue most..most guys picked red! Brunettes are awesome too of course :P
I don't know if every guy has a thing for redheads. I've been called unsavory names by guys for having red hair many times. However, I dyed my hair red in the first place because my boyfriend likes the color.
I knew 2 guys who said they did not like redheads at all.