Why someone have hairfall especially in teenage? my friends say it has something to do with sexuallity or something like that is that true?

What you refer to as "hairfall" may be alopecia, the term for hair loss. Hormonal changes occurring during puberty, thyroid abnormalitites, and repeated hair pulling ("Trichotillomania") or certain hair chemicals and hair styles (such as tight braids and cornrolls) may contribute. Talk to a health care provider in your area.

The only relationship between sex and hair loss is the male sex, in genetically predisposed males, may have profound hair loss known as male pattern balding. This is testosterone dependent. There are other forms of autoimmune and hormonal hair loss Women also experience hair loss or thinning a process typically noticed in the perimenopausal (around the start of menopause).