TABOO AND GENETICS 13 



of and so help people to sensibly make up their 

 minds what can be done about it. 



To define sex with rigid accuracy as the term 

 appHes to human beings, it is necessary to tell 

 what it is in mammals, since man is a mammal. 

 The presence of distinct body-cells is not 

 pecuUar to mammals, but there is one respect 

 in which these latter are quite different from 

 non-mammals : A mammahan individual, be- 

 ginning Hke a non-mammal with a fertilized egg, 

 has a period of intra-maternal development 

 which a non-mammal has not. That is, a 

 non-mammahan is a fertihzed egg plus its 

 parental (or extra-parental) environment ; but 

 a mammahan individual is a fertilized egg, plus 

 Us intra-maternal environment, plus its non- 

 parental environment. 



Here in a nutshell is the biological basis of 

 sex problem in human society. Human in- 

 dividuals do wear out and have to be replaced by 

 reproduction. In the reproductive process, the 

 female, as in mammals generally, is specialized 

 to provide an intra-maternal environment 

 (approximately nine months in the human 

 species) for each new individual, and lactation 

 or suckling afterward. The biological phase of 

 the sex problem in society consists in studying 

 the nature of that specialization. From the 

 purely sociological standpoint, the sex problem 

 concerns the customs and institutions which 



