Hofacker’s actual figures were the following:
| Father younger than mother | 90.1 boys to 100 girls. |
| Father same age as mother | 93.3 boys to 100 girls. |
| Father 4 to 6 years older than mother | 108.8 boys to 100 girls. |
| Father 6 to 9 years older than mother | 124.7 boys to 100 girls. |
| Father 9 to 12 years older than mother | 143.7 boys to 100 girls. |
Sadler’s results were closely similar:
| Father younger than mother | 86 boys to 100 girls. |
| Father same age as mother | 94 boys to 100 girls. |
| Father 1 to 6 years older than mother | 103 boys to 100 girls. |
| Father 6 to 11 years older than mother | 126 boys to 100 girls. |
| Father 11 to 16 years older than mother | 147 boys to 100 girls. |
| Father 16 years and more older than mother | 163 boys to 100 girls. |
Goehlert found that the offspring of marriages in which the husband was younger than the wife were 71 boys and 86 girls; of marriages in which husband and wife were of the same age, 263 boys and 282 girls; and of marriages in which the husband was older than the wife, 2,017 boys and 1,865 girls.
Wappaeus, combining the data supplied by these three investigators, Hofacker, Sadler and Goehlert, obtained the following sexual ratios for the entire 8,000 cases (i. e., the number of boys born to each 100 girls born): When the husband was younger than the wife, 88.2; when husband and wife were of the same age, 93.5; when the husband was older than the wife, 113.0.
It will be observed that the mean sexual ratio of these 8,000 cases is 109.6; whilst, as we saw above, when a sufficiently large number of instances is taken, the sexual ratio always closely approximates to 106.3. From this it appears that the numbers dealt with by Hofacker, Sadler and Goehlert in their investigations were too small for the deduction of trustworthy averages.
The same criticism is applicable to the observations of Ahlfeld, Breslau and Noirot, whose results conflict with those just given. According to Ahlfeld, in the case of 1,376 births where the father was at least 10 years older than the mother, the sexual ratio was only 98.2. According to Noirot’s data, in cases in which the father was older than the mother, this ratio was 99.7.
Oesterlen gives the following brief summary of the researches made for the establishment and confirmation of the law of Hofacker and Sadler:
| Author. | Father older than mother. | Father and mother same age. | Mother older than father. | Sexual ratio. | Number of instances. |
|---|---|---|---|---|---|
| Hofacker | 117.8 | 92.0 | 90.6 | 107.5 | 1,996 |
| Sadler | 121.4 | 94.8 | 86.5 | 114.7 | 2,008 |
| Goehlert | 108.2 | 93.3 | 82.6 | 105.3 | 4,584 |
| Noirot | 99.7 | 116.0 | 103.5 | 4,000 | |
| Legoyt (Calais) | 109.9 | 107.9 | 101.6 | 107.9 | 6,006 |
| Legoyt (Paris) | 104.4 | 102.1 | 97.5 | 102.9 | 52,311 |
| Breslau | 103.9 | 103.1 | 117.6 | 106.6 | 8,084 |