The discussion of the origins of patriarchy, in some of the answers to Preventing post-apocalyptic society from becoming misogynistic, has me wondering if a government couldn't be designed to put a premium on raising children.
Imagine a new space colony which, due to the lack of room on the generation ship, is facing under-population issues. To combat these issues, the colonists adopt a weighted, pure democracy as their governmental structure. Each family unit will receive one vote for each of their children, divided by the number of parents in the family unit.
So, a monogynous couple with four children would get 2 votes, while a polygamous couple with two wives would need six children to match the monogynous couple's voting power.
The idea is to maximize not only the number of children, but also the ratio of parents to children; in the hopes of providing all of the children with adequate parenting. We don't want some power-mad politician sire-ing his own political party.
And since only parents can vote, hopefully all decisions will be made with the long term health of the colony in mind.
How can someone game this system? What subtle loopholes have I left open which would allow a creative and virile/fertile person to obtain disproportionate power?