What does raising children have to do with society? Decision of having and raising a child is a fundamentally personal, not societal decision. Each pair should decide how they want to split responsibilities of raising a child before its conception, based on their preferences, and society should not force them to any model.
Also, it seems to me that society already prioritize child-raising too much compared to other non-work activities. If people would leave STEM/some other field due to work-life balance for some other personal goals than child-raising (say part-time working in a non-profit), would anyone care?