Why are those the only two choices? This is definitely how every woman I have dated (including my wife) has seen it - if we ain't raisin' kids in a house we damn well better be burning a fuckton of jet fuel. Not willing to entertain "just work a lot less" as even a joking third path.

I opted for a kid and a mortgage because at least this way maybe one day me "and my son" will build an electromagnetic rail accelerator[1] and remote-controlled gliders and fly them around together.

The serious answer to that question is probably because straight couples mostly have biological children, with the associated biogenic time pressure driving FOMO. Adoption or surrogacy can in theory be put off indefinitely and I imagine a lot of male-male couples wind up doing just that.

[1] Terminology intentionally changed from "rail-gun" to emphasize peaceful applications to my gun-hating wife.