There is a correlation between mate choice, odour preference and genetic similarity at the MHC. An evolutionary explanation is that females are attracted to males with MHC alleles different from their own, to provide their offspring with a stronger immune system. Females currently using hormonal contraceptives preferred the scent of men with MHCs similar to their own. Olfactory cues can be used to recognise kin. Over thirty olfactory receptor genes have been located at the HLA class I region,  which presents peptides from inside the cell to be destroyed by the immune system.
Why Does My Vagina Smell? February 16, You Asked It: Is something wrong with me? Your vagina has a unique mixture of bacteria the good kind that makes sure your vagina is as healthy as possible. In addition, your sweat glands become more active during puberty and begin to release new chemicals. Because of this, most teens need to wear antiperspirant or deodorant during the day. You also have them on your vulva the outside genitalia and your groin area.