A common criterion is a dorsal (measured on top) penile length of at least 2.5 standard deviations smaller than the mean human penis size for age.

[citation needed] In addition, in utero exposure to some estrogen-based fertility drugs like diethylstilbestrol (DES) has been linked to genital abnormalities or a smaller than normal penis.

[4] After evaluation to detect any of the conditions described above, micropenis can often be treated in infancy with injections of various hormones, such as human chorionic gonadotropin and testosterone.

[citation needed] In extreme cases of micropenis, there is barely any shaft, and the glans appears to sit almost on the pubic skin.

With parental acceptance, the boy would be reassigned and renamed as a girl, and surgery performed to remove the testes and construct an artificial vagina (vaginoplasty).

This was based on the now-questioned idea that gender identity was shaped entirely from socialization, and that a man with a small penis can find no acceptable place in society.