=Women Can Not be Forced Back to Compulsory Marriage.=--It is too late in the day to pass laws forbidding women from gaining economic freedom and social power in professional careers so that all the best of them shall again be obliged to marry as a "means of support." Few persons would do this if they could. But we can and should make haste to bring together, as the State Universities of our country do so helpfully, those who should be the fathers and mothers of the future, in that period of life when love will take chances for the future. "Propinquity," the old adage declares, is the "best incentive to courtship," and it should be made to work more effectively. In our own country, eugenists may be comforted to learn, it is still fashionable to marry, even in the best families. We are told by our census that more people marry in the thousand and marry young in the United States than in other countries.[2] And although it may be claimed that the older Americans and the finest types do not reproduce so freely as social well-being requires, there is much hope that movements of population, so much freer here than elsewhere among the educated and competent, will lead to better sex-adjustments and to the absorbing of more first-class women in family life. =A Few Believe in a "Third Sex."=--There are those, however, although but a few, who do not view with alarm the modern increase of unmarried women of types most needed for motherhood. These believe that in the present time, and perhaps in a long future, our complex social needs cannot be met by holding the best blood and breeding within the family bond, but that there must be a reserve of celibates, a few men and many women, to carry on the school and to work for social amelioration and social progress. This point of view, which has been sometimes characterized as "defense of a third sex," is based on two premises: namely, first, that all of a married woman's time and strength throughout her whole adult life must go into strictly family service in order for the family to be maintained; and, second, that those men and women who specialize in some vocation in such extreme degree that they cannot marry and have children are thereby, by reason of that celibate concentration, better able to function socially in their chosen work. It is the object of this book to disprove both these assumptions.