Which would be the best weakness when explaining behaviour as being down to Nurture?

A weakness of explaining behaviour as being due to nurture is that its reductionist as it ignores the influence of genetics. For example, in Banduras study, he didnt look at the biological causes of the aggressive levels in males in the study, especially who were more aggressive than females. Therefore, it can be argued theres not a full explanation for why people behave in certain ways, as it cant just be simply down to the individual themselves.