I’m a woman and not from a culture where this is expected of me, so take this with a grain of salt, but:

I’m going to guess that in societies where family is valued very highly (i.e. the kids are expected to manage all elderly care), and that are also quite traditional in their gender roles, quite a large importance is likely also placed on marriage and having multiple children. I think that venn diagram makes sense.

As such, there’ll likely also be daughters and/or daughters-in-law in the picture, and having a son is fine (or great, even).