This section is from the book "The Transmission Of Life. Counsels On The Nature And Hygiene Of The Masculine Function", by George H. Napheys. Also available from Amazon: The Transmission of Life.
The question whether intermarriage of near relatives can be approved is one which within the last few years has excited lively discussion among physicians. The most skilful are found on opposite sides, and the arguments adduced against it seem very strong. While granting this, we must express our own views candidly that they only seem strong, and that if closely scrutinized they are found to be based on erroneous statistics, and compiled by persons who are prejudiced already in favor of their own views.
In a similar work to the present, addressed, however, to the other sex, we made use of the following language, which exposed us to severe criticism from several eminent statisticians and medical writers : " The fear of marrying a cousin, even a first cousin, is entirely groundless, provided there is no decided hereditary taint in the family. And when such a hereditary taint does exist, the danger is not greater than in marrying into any other family where it is also found. But as few families are wholly without some lurking predisposition to disease, it is not well, as a rule, to run the risk of developing this by too repeated unions."
Decided as this language is, our further investigations since we made use of it do not lead us to weaken its force. On the contrary, we find ourselves supported in it by one of the most cautious and dependable authorities in the medical world, the Lancet of London. In the editorial columns of a late number of that journal the following statement is made as the result of the most recent and extended researches on that point: -
"The marriage of cousins, providing both are healthy, has no tendency to produce disease in the offspring. If, however, the cousins inherit the disease or the proclivity to it of their common ancestor, their children will have a strong tendency to that disease, which might be fostered or suppressed by circumstances. There can be no question that cousins descended from an insane or highly consumptive grand-parent should not intermarry; but we cannot see any reason for supposing that either insanity or consumption would result from the intermarriage of healthy cousins."
In conclusion, while for a man to marry a near relative when they both belong to a consumptive, a scrofulous, or a weak-minded race, is eminently reprehensible, it is not con-trary to ascertained laws for him to unite himself to his cousin when the family is thoroughly healthy.