There should be an Erectile Dysfunction Elder Trait.
Look, we're all adults here (or at least we all pretend to be). It doesn't make sense that my 80 year old, nearly blind, arthritic, and borderline senile Sultan is still regularly siring children with his 4 wives just because the wives are in their 20s. Viagra doesn't exist, there's no way the man has the blood pressure necessary to maintain an erection, let alone the stamina for the performance. The game already decreases fertility somewhat with age but the new Elder Traits provide a framework for a greater solution: add an Erectile Dysfunction Elder Trait.