where the race and the individual would both be gainers by a marriage which produced children that had the family taint, but either latent or not to a degree serious enough to counteract their value. The individual must decide for himself with especial reference to the trait in question and his other compensating qualities; but he should at least have the benefit of whatever light genetics can offer him, before he makes his decision.
For the sake of a concrete example, let us suppose that a man, in whose ancestry tuberculosis has appeared for several generations, is contemplating marriage. The first thing to be remembered is that if he marries a woman with a similar family history, their children will have a double inheritance of the taint, and are almost certain to be affected unless living in an especially favorable region. It would in most cases be best that no children result from such a marriage.
On the other hand, the man may marry a woman in whose family consumption is unknown. The chance of their children being tuberculous will not be great; nevertheless the taint, the diathesis, will be passed on just the same, although concealed, possibly to appear at some future time. Such a marriage is in some ways more dangerous to the race, in the long run, than that of "weakness with weakness." Yet society at present certainly has no safe grounds for interference, if such a marriage is made. If the two persons come of superior stock, it seems probable that the gain will outweigh the loss. In any event, it is at least to be expected that both man and woman would have a deliberate consciousness of what they are doing, and that no person with any honor would enter into a marriage, concealing a defect in his or her ancestry. Love is usually blind enough to overlook such a thing, but if it chooses not to, it ought not to be blindfolded.
In short, the mating of strength with strength is certainly the ideal which society should have and which every individual should have. But human