In 64 cases of Turner's syndrome (34 XO, 21 with mosaicism and 9 with partial deletion of one X chromosome) there was a closer correlation with mother's height (r = 0.607, p less than 0.001) than with father's height (r = 0.28, p less than 0.05) suggesting that Turner's syndrome could result from deletion of one paternal gonosome more than of one maternal gonosome. Moreover, 6.4% of Turner patients have a mother whose adult height is below -2 DS, contrasting with 3% in other people.