It is not possible to measure in the abstract the burden of the generative function for woman, just as it is not possible to measure her grasp on the world: the relation of maternity to individual life is naturally regulated in animals by the cycle of heat and seasons; it is undefined for woman; only society can decide; woman's enslavement to the species is tighter or looser depending on how many births the society demands and the hygienic conditions in which pregnancy and birth occur.