The conclusion of this matter is that scientific inquiry completely demonstrates the equal importance of the selection of fathers and of mothers. If our modern knowledge of heredity is to be admitted at all, it follows that the choice of women for motherhood is of the utmost moment for the future of mankind. Woman is half the race; and the leaders of the woman's movement must recognize the importance of their sex in this fundamental question of eugenics. At present they do not do so; indeed, no one does. But the fact remains. As before all things a Eugenist, and responsible, indeed, for that name, I cannot ignore it in the following pages. There is not only to-day to think of, but to-morrow. The eugenics which ignores the natural differences between women as individuals, and their still greater natural differences as potential parents, is only half eugenics; the leading women who in any way countenance such measures as deprive the blood of the future of its due contribution from the best women of the present, are leading not only one sex but the race as a whole to ruin. If women were not so important as Nature has made them, none of this would matter. To insist upon it is only to insist upon the importance of the sex. The remarkable fact, which seems to me to make this protest and the forthcoming pages so necessary, is that the leading feminists do not recognize the all-importance of their sex in this regard. They must be accused of neglecting it and of not knowing how important they are. They consider the present only, and not the composition of the future. Like the rest of the world, I read their papers and manifestoes, their speeches and books, and have done so, and have subscribed to them, for years; but no one can refer me to a single passage in any of these where any feminist or suffragist, in Great Britain, at least, militant or non-militant, has set forth the principle, beside which all others are trivial, that _the best women must be the mothers of the future_. Yet this which is thus ignored matters so much that other things matter only in so far as they affect it. As I have elsewhere maintained, the eugenic criterion is the first and last of every measure of reform or reaction that can be proposed or imagined. Will it make a better race? Will the consequence be that more of the better stocks, _of both sexes_, contribute to the composition of future generations? In other words, the very first thing that the feminist movement must prove is that it is eugenic. If it be so, its claims are unchallengeable; if it be what may contrariwise be called _dysgenic_, no arguments in its favour are of any avail. Yet the present champions of the woman's cause are apparently unaware that this question exists. They do not know how important their sex is.