Every higher evolutionary differentiation results inevitably not only in progressive mutations in the traits of species, but, as well, in variations of the reproductive processes of such. When _defects_, physical or mental, are not reproduced in later generations true to Mendelian law, however, this is not abnormal, but is beautifully normal. Normality requires that defect--which is a deviation from The Normal--shall not be transmitted in any ratio whatsoever, but shall be corrected in a succeeding generation. Moreover, when we realise the number and the complexities of human traits, all struggling to keep The Law, it is only to be expected that any single characteristic owing to its sex-inherence, may pass into the potential or Recessive, mode, and may thus vanish for a generation. Further, by the law of compensation, any trait or determinant, although itself Dominant, may be dwarfed and submerged by some other Dominant trait more assertive than itself. Suppose a father normally larger and stronger than the normally shorter and weaker mother: Stature and strength being both Dominant and masculine traits, the traits of such a father, dominating the development of his sons, should so over-ride the traits of lesser strength and stature of the mother (in whom strength and stature are normally Recessive) that his sons will be tall and broad and strong, and mentally virile. On the other hand, the mother's traits, prepotent in the development of daughters, will inhibit in these and diminish the strength and stature of their paternal inherences. Thus, the woman of pure Recessive (the essential woman) type is smaller, more delicately organised, and weaker than the male. By such means, the normal of the relative strength, stature, and mental qualifications of the sexes is preserved; the specialised characteristics of both ever further diverging in trend, while at the same time intensifying their intrinsic attributes. Suppose, however, a mother who deviates from the normal in having developed along masculine lines, and who is, accordingly, tall or strong or mentally virile: Far from supplementing, in her sons, the father's traits of strength and stature, her sons will be more or less emasculate in mind or body, or in both. Strength and stature and virile mentality not being normal to her, these can only have emerged in her and can only have been exercised by her at cost of the masculine potential she bore in trust for male offspring. A woman who wins golf or hockey-matches may be said therefore to energise her muscles with the potential manhood of possible sons. With their potential existence indeed, since over-strenuous pursuits may sterilise women absolutely as regards male offspring.