I don't think, Giant is impregnatable yet. her dlc is only in the files as preparation for the next update. Or do you mean large female native, the big abs mommy with inverted nipples? she should be normal, just equip her the pregnancy booster, craftable from the campfire.How to increase giant pregnancy rate?
I really hope, in the future, after the story finishes, you could just swap the mc. what I mean by that is, you can make any npc a playable character. that's to further increase post endgame content. Like in a sandbox.
for example you could run around as a large female native, a large man native or even as a werwolf.