When fertilization occurs, and the sperm cell fuses with the egg, the following may take place: (1) a ten chromosome sperm may unite with the eleven chromosome egg, and produce a twenty-one chromosome individual or (2) an eleven chromosome sperm may unite with an eleven chromosome egg producing a twenty-two chromosome individual. It has been found that the twenty-two chromosome individual invariably develops into a female, and the twenty-one into a male. Therefore, femaleness is a positive quality, dependent upon the action of the X-chromosome, and maleness an absence of femaleness, due to lack of the extra, odd chromosome. In man, two X-chromosomes have been discovered, half the sperm containing 12, and the other half containing only 10 chromosomes. The number of chromosomes in human cells consequently is 22 in the male and 24 in the female. The X-chromosome is the bearer of sex destiny. There still remains the work to be done on the actual control of sex by man, apart from its natural determination. For the time being, let the feminists glory in the fact that they have two more chromosomes to each cell than their opponents. Certainly there can be no talk here of a natural inferiority of women. THE SECONDARY OR ENDOCRINE SEX TRAITS Yet the matter is after all not so simple as this would make it out to be. All that can be safely laid down is that the character of the reproductive organs is determined by the extra chromosomes. And though these reproductive organs have a good deal to do with the masculine or feminine quality of the organism as a whole, through their internal secretions, they are not alone. All the other internal secretions have their say in the final outcome, determining what may be called the dominant sex quality, but leaving inherent the latent soil of the other sex. This may become active and dominant in its turn, under certain conditions of stimulation, abnormality, or disease, dependent upon a rearrangement of status and influence among the ductless glands. Bisexuality preceded monosexuality in the animal pedigree, and co-exists with it even at the highest points of the genealogical tree. While from the standpoint of the species, the criterion of the sex classification of its members will depend upon their capacity to fertilize or to be fertilized, a quality that may, therefore, be spoken of as the primary sex character, a number of other traits have been evolved by sexual selection, the secondary sex traits. They have come to be just as important, to the individual, as far as his or her consciousness of sex attitudes and reactions to it are concerned. The terms primary and secondary sex characteristics, though inapt, must be allowed to stand.