SEX. 305 



312 fathers 2- 3 years older than mothers ... . . 101.8 



211 " 4- 6 " " " " , .- 108.0 



200 " 6-10 u " " " . ... . 130.1 



168 " 10-16 u " " " . . . - 144.3 



120 " 17-25 ** " " " . . . '. 189.7 



80 " 26-32 " " " " . ' . .' ' 125.6 



45 " 33-40 " " " " . 112.6 



18 " 40-50 " " " (mother under 25) 115.4 



13 " 40-50 " " " ' ( " over 25) 91.6 



MOTHERS OLDER THAN FATHERS. 



88 mothers from 1- 3 years older 94.3 



77 " " 3-5 " " .,.. -*.i, i . 4 u 88.8 



66 " u 5-10 " " 77.1 



43 " " 10-15 " " ; '"'; V" . . 60.6 



17 " " 15-22 " " . ... . 48.3 



Notwithstanding the apparent uniform increase in 

 the proportion of male births in the cases in which 

 the father is from six to twenty-five years older than 

 the mother, it would not be safe to attribute the vari- 

 ation to age alone. 



In the first 1,189 cases in the table, in which the 

 parents are of equal age, or the fathers are from one 

 to six years older than the mothers, the average pro- 

 portion of male births is below the general average, 

 as shown by other statistics ; but, as the fathers have 

 the advantage of the mothers in age in 799 of these 

 cases, the proportion of male births should be consid- 

 erably higher. Instead of comparing the special cases 

 collected with one another, would it not be more satis- 

 factory to compare them with the average of all cases 

 that can be obtained, without reference to age ? 



In the first 1,189 cases above noticed there would 



be, according to the table, 593 male children and 596 

 14 



