Various factors that lead to the special development of sexual characteristics, generally called intersex-factors. These factors can cause certain features in the structure of the external genitalia, internal genital organs, sex chromosomes or sex hormones. The most common among them are the following:
- external genitalia, which cannot be categorized unequivocally as male’s or female’s;
- incomplete or unusual development of internal genital organs;
- inconsistency between the external genital organs and internal genital organs;
- peculiarities of formation of sex chromosomes;
- peculiarities of development of testicles or ovaries;
- excessive or insufficient production of sex hormones;
- the inability of the body to respond to sex hormones.
“Intersex” [lat. Inter … – between, in the middle and in the lat. Sexus – sex] was originally a medical term, which was later begun to apply more widely to people with specific characteristics of sexual development. Many intersex experts also recommended using as a term the word-combination: “peculiarities of sexual development”.