Frozen Evolution. Or, that’s not the way it is, Mr. Darwin. A Farewell to Selfish Gene.

 Affecting the sex of offspring is one of the areas in which a conflict of interests can occur between the interests of males and females. The most extreme cases occur once again amongst hymenopterous insects, where the males do not have the least interest in their sons with whom they do not share any part of their genome (daughters obtain half their genes from their father and half from their mother, sons have all their genes from their mother). In the mentioned parasitic wasps of the Nasonia genus, the male cannot affect the decision of the female in any way; in another hymenopterous insect Tripoxylon politum, it seems that it at least tries to (Dawkins 1976). In this case, the female lays the eggs immediately following copulation. The male holds the female by the head for about 30 seconds after copulation and apparently attempts to prevent her from laying any eggs. It cannot be excluded that, through this forced prolonging of the interval between copulation and laying of the eggs, it could perhaps increase the chance that the eggs will be fertilized prior to laying.

            The conflict of interests between the male and female is not as strong in diploid organisms, but still occurs to some degree. This could follow, for example, from the fact that the female must invest substantially more in the production of offspring than the male. Consequently, for example, situations can occur where it would be more advantageous for the father to kill embryos or zygotes of a certain sex, while this would not be worthwhile for the female.