INFLUENCE OF ORDER OF BIRTH, ETC. 321 



which have often been quoted in discussions of this subject. 

 Among the parents of 456 criminals it was found that both young 

 and old parents produced more criminals than were born from 

 people of maturity (20-40 years). Thieves predominate among 

 the children of young parents while swindlers and those guilty 

 of crimes of violence were more common among the children of 

 parents of over 40 years. Studies of the intelligence of 917 

 school children in relation to the age of their fathers gave a high 

 percentage with good intelligence from fathers below 25 years. 

 The children of young mothers (21 years or less) were found to 

 produce about as high percentage of intelligent pupils as the 

 children of young fathers. The very superior children, however, 

 were somewhat more frequently born of parents of mature age. 

 Children of old parents made in general the poorest showing. 

 However, the children of old fathers made the best record in 

 respect to conduct at school, but curiously enough the children 

 of older mothers were the worst of all. It is noteworthy that 

 the relation between intelligence of offspring and age of parents 

 is just the reverse of what it is claimed by Rediield, and the 

 relation of crime to parental age seems to be at variance with 

 the findings of Goring who found that criminals were especially 

 frequent among the first born. 



There is so much opportunity for social factors to affect such 

 results as were found by Marro that any real biological influence 

 of parental age is not apparent. Grouping of parents into young 

 and old necessarily involves to a certain degree a selection of 

 stock. This circumstance together with the environmental factors 

 which are also more or less different for the children of old 

 and young parents may influence to a considerable degree the 

 intelligence and conduct of school children and even proclivities 

 to crime in later years. 



Undue frequency of births is undoubtedly correlated with 

 the high early death rate of children. Data compiled by Ansell 

 from well-to-do English families showed that where the interval 

 between births was less than a year the infant mortality was 

 nearly twice as great as when the interval was between one and 



