https://constitutioncenter.org/timeline/html/cw08_12159.html

Women as moral citizens

As a “colonial frontier”, New Zealand had a surplus of men, especially in resource towns. Pragmatically, this placed a premium on women for their part as wives, mothers and moral compasses.

There was a fear of a chaotic frontier full of marauding single men. This colonial context saw conservative men who supported family values supporting suffrage. During the 1880s, depression and its accompanying poverty, sexual licence and drunken disorder further enhanced women’s value as settling maternal figures. Women voters promised a stabilising effect on society.

1.) Culturally, there was a broad understanding that males remain within their birth family lineages, whereas women leave and join their husband's family.

2.) Male children were expected to provide for their parents in old age, whereas (again if I recall correctly) it was customary to offer a dowry when female children were married.

3.) As a result wealth tended to transfer from female-heavy lineages to male-heavy lineages.

4.) When new land was available, or technology or new crops could make old land more productive, this effect was manageable, but increased pressure when population butted up against technical limits of agriculture, so that additional new arable land (wealth) could not be easily made available. Particularly when infrastructure and ecological failures strained or reduced the capacity of productive land. In that more zero-sum environment, male children were correspondingly more valuable, and there were upticks in female infanticide.

There's another dynamic in play with regards to the Chinese bureaucratic governmental system, which only men could take advantage of - in the archtypical system, entry into the bureacratic class was at least nominally meritocratic, and through grueling work and education, one could become eligible to take and pass the examinations to gain the bureaucratic degrees, which conferred massive benefits, which were again expected to accrue to not only the newly-minted official, but their family groups. So there are instances of family lineages and even entire villages pooling their resources behind a favored son, investing massively in classical education in hopes of hitting the lottery that way.

I've often wondered to what extent it explains the situation in Afghanistan. If there is a shortage of women anyway due to poor healthcare and other factors, and some men get to have multiple wives, what do the other men do?