The following table compiled from Mulhall[[35]] and other sources fails to show any correspondence between the percentage of first cousin marriage and the masculinity:
| TABLE XI. | ||
|---|---|---|
| Country. | Masculinity. | Per cent 1st cousin marriage. |
| England | 104.5 | .75 |
| France | 105.3 | 1.26 |
| Italy | 107.0 | .69 |
| Prussia | 105.8 | .67 |
| U.S.[[36]] | 104.9 | 1.00 |
| Jews[[37]] | 107.6 | 2.30 |
It is impossible to obtain the actual masculinity ratio for the United States, for the Census gives the statistics for only one year in ten and even then is untrustworthy on this point. In a few states birth registration is attempted but the figures thus obtained do not harmonize with the Census and the situation is not greatly improved.[[38]] The masculinity varies considerably in different parts of the country, and is generally higher in states where the rural population predominates. This fact agrees with European statistics which almost universally show a high masculinity in rural districts. Table XII, illustrates this point:
| TABLE XII. | |||||
|---|---|---|---|---|---|
| Masculinity in Scotland.[[39]] | |||||
| Period. | Principal towns. | Large towns. | Small towns. | Mainland rural districts. | Insular rural districts. |
| 1855-1861 | -- | -- | -- | 105.6 | 106.6 |
| 1862-1871 | -- | -- | -- | 105.9 | 105.6 |
| 1872-1881 | 105.0 | 105.6 | 106.1 | 105.3 | 108.0 |
| 1882-1891 | 105.1 | 105.6 | 105.5 | 105.5 | 108.7 |
| 1892-1901 | 104.7 | 104.6 | 104.9 | 105.2 | 107.1 |
| Average | 104.9 | 105.3 | 105.5 | 105.5 | 107.2 |
This would seem to bear out the theory that masculinity is affected by consanguineous marriage, for consanguineous marriage is more frequent in rural districts, and especially in insular rural districts. But unless consanguineous marriages can directly be shown to produce an excess of male births greater than the normal, such indirect evidence is valueless.
In the genealogical material previously considered, we have a sampling of the American population throughout its whole history, but the data so far collected are insufficient for more than an indication of what might be expected in further research along the same line. In the following table as before, the figures compiled from printed genealogies are separated from those obtained through correspondence and from miscellaneous sources. The "unrelated" marriages from genealogies, are marriages of brothers and sisters of the persons who have married first cousins, and their records were obtained from the same sources as those in the next previous category. The "children of first cousins" are the offspring of the first cousin marriages who married persons not related to themselves by blood. The last category includes distantly related marriages from correspondence and other sources and marriages between persons of the same surname whose relationship could not be traced.
| TABLE XIII. | |||||
|---|---|---|---|---|---|
| Marriages. | Number Fertile. | Sex of Children. | Masculinity. | ||
| Male. | Female. | Unknown. | |||
| 1st cousin. Gene. | 125 | 318 | 314 | 40 | 101 |
| Unrelated. Gene. | 629 | 1561 | 1559 | 64 | 100 |
| Ch. of 1st cousins. Gene. | 170 | 402 | 375 | 48 | 107 |
| Other cousin. Gene. | 301 | 736 | 666 | 15 | 111 |
| 1st Cousin. Cor. | 150 | 316 | 295 | 148 | 107 |
| Ch. of 1st cousins. Cor. | 124 | 192 | 164 | 214 | 111 |
| Miscellaneous | 88 | 210 | 205 | 50 | 102 |
| Total | 1587 | 3735 | 3578 | 578 | 104.4 |
It is of course impossible to explain all the ratios in this table. Much variation is here due to chance, and a few additional cases might appreciably change any of the ratios. It will be noticed, however, that the two categories whose masculinity is most similar (100 and 101), are derived from cases taken from the same families and from the same environment, and differing only in that the first is closely consanguineous while the second is not. The third and fourth groups, separated from the first two by at least a generation, and probably living in a different environment, differ greatly in masculinity from them. In the fourth group are included 1-1/2, second, third, and a few even more distant cousins, all more distantly related than first cousins, and taken from the same genealogies as these; yet the masculinity is much greater.
An analysis of the cases collected fifty years ago by Dr. Bemiss, of course without thought of masculinity, gives the following result:[[40]]
| TABLE XIV. | ||||
|---|---|---|---|---|
| Marriage. | Sex of Children. | Masculinity. | ||
| Number. | Male. | Female. | ||
| 1st cousins and nearer | 709 | 1245 | 1171 | 106.3 |
| 2d and 3rd cousins | 124 | 264 | 240 | 110.0 |
| All consanguineous | 833 | 1509 | 1411 | 106.9 |
| Unrelated | 125 | 444 | 380 | 116.9 |