The authors report three cases of anidrotic ectodermal dysplasia with an X-linked form. Two cases are sporadic forms, followed up during ten years; the third case is a familial form followed-up through six generations. With their personal cases, the authors insist on the repercussions in the everyday life; they report the signs which must search for an heterozygosis among the females of this families: hypoidrosis, hypodontia, hair shaft abnormalities under polarized light, special look of the face of those females who are alike sometimes wonderfully.