[Footnote 46: De Lapouge, _Les Selections Societies_, p. 196.]
It is almost impossible to get any accurate statistics of sterility from genealogies, for when no children are given in the record, there is always a strong possibility that there were children of whom the genealogist has no record. However, of 16 first-cousin marriages of which the record expressly stated "no issue," or where it was practically certain that no issue was possible, the average age of the brides was 34.3 years and that of the grooms was 39 years, showing that consanguinity could not have been the only cause of their sterility.
In regard to relative fertility the figures are reliable, but they fail to indicate any effect of consanguinity upon fertility, as will be noted in Table XVII.
TABLE XVII. ------------------------------------------------------------- |No. of | | Ave. to |fertile | No. of | fertile Parentage. |marriages.|children.|marriage. ------------------------------------------------------------- First cousin. Gene. | 125 | 672 | 5.4 First cousin. Cor. | 150 | 759 | 5.1 Double cousins and uncle-niece| 9 | 39 | 4.3 Other consanguineous | 333 | 1605 | 4.8 Non-related | 676 | 3417 | 5.1 Ch. of 1st cousins | 294 | 1395 | 4.7 All consanguineous | 617 | 3075 | 5.0 All non-related | 970 | 4812 | 5.0 -------------------------------------------------------------
The report of Dr. Bemiss, and the report of the Ohio commission[47] which he quotes, give the following figures:[48]
TABLE XVIII. ------------------------------------------------------- | No. of | | Ave. to | fertile | No. of | fertile Parentage. |marriages.|children.|marriages. ------------------------------------------------------- 1st cousins or nearer[A]| 660 | 3363 | 5.0 More distantly related | 119 | 572 | 4.8 Non-consanguineous | 125 | 837 | 6.7 Ohio consanguineous | 155 | 1021 | 6.6 Ohio non-consanguineous | 200 | 1375 | 6.9 ------------------------------------------------------- [A] Includes double-cousins and uncle-niece marriages.
[Footnote 47: Appointed to ascertain the number of the deaf and dumb, blind, idiotic and insane within the State.]
[Footnote 48: See Bemiss, in _Trans. of Am. Med. Asso._, vol. xi, 1858, pp. 420-425.]