The right kind are married couples. Unfortunately for the "alternative lifestyle" crowd(yourself perhaps?), study after study has shown that children raised with a male father and female mother that are married aren't as screwed up as children in single parent homes. Right now the government encourages single teenage girls to have a baby outside of marriage. Over 70% of black babies are born out of wedlock and look at the incarceration rates of black males. My wife and I are penalized right now by the tax structure for being married and employed. We can't afford to have children, but we are penalized for being married. Why not encourage couples to stay married and encourage married couples to have children? Nahh, lets encourage gay "couples" to adopt babies and ignore illegal immigration to keep the population up to pay for social security instead.
Unfortunately for the "alternative lifestyle" crowd (yourself perhaps?)Perhaps you would think so. I'm divorced. Getting divorced beat suicide. I adopted my ex's child from a previous (anulled) relationship. We started one from scratch. Statistically we didn't quite replace ourselves.
Since we are asking personal questions, how many children do you have/plan to have?
An absolute flat tax would neither reward nor punish someone for decisions about marriage, children, whether to rent or buy a home, what business to engage in. They could make their personal decisions based on what made sense to them, not some social(ist) "engineer".
BTW, "Social engineer" is a term I loath. In no field of engineering would such a disconnect between results and intents be tolerated!