The Navajo culture. Why? Because their society is predominately matriarchal and incorporates a clan or Ke system. It is the females in their society that do the majority of the planning and setting of direction for the community. The Ke system regulates social conduct and behavior, and guides personal interaction.
What does that have to do with my SciFiRom? Actually, quite a lot. The male protag in my story is from a male-dominated, warrior society, but their system of naming and recognizing a primary heir puts huge importance on the female family. Learning more about the Navajo traditions is giving me some great insights on customs, quirks and paradoxes that I can throw into the mix.
If you have any interest in a bit of enlightenment about the Navajo culture, this site has a good paper on the subject done by a land use planning committee: http://www.cbcrc.org/2003speakerpapers/Calsoyas%20-%20Navajo%20Four%20Directions%20Research%20Model%20Paper.pdf