Luckily, almost no one on earth agrees with you.
Your position isn't conservative--as you claim--it's ultra-libertarian. That's fine. Admit what you are. Embrace it. But you aren't a conservative, and you can't admonish conservatives for not being libertarians.
Untouched are my questions about the regulation of family practices. Does government have the right to require Christian Scientists to get medical attention for their children? What about corporal punishment? Obviously there is a point where this becomes harm. It isn't obvious to me that this point of law should be left up to individuals alone. Your argument has a problem, because in many cases it's up to the polity to decide when in fact any actual harm has occurred.
Untouched also the question of abortion. Regulation of personal reproductive procedure, or is there a human harmed in the process? Government needs to make that call, one way or the other, as a matter of life or death.
All pure libertarian arguments ultimately fail because the answer to the question of actual harm is seldom clear cut, and must be decided--by government--in advance. That is why government of, by, and for the people matters.
These issues do not concern consenting adults. I never said there wasn't a proper role for government in regulating behavior towards children or non-consenting adults. Obviously these issues you mention -- and a lot of others -- present a lot of gray area over which reasonable people may debate exactly where government involvement is warranted. The decisions of one or more adults to set up housekeeping and raise a family does not. One-man-one-woman marriages are hardly devoid of horrible cases of child abuse and neglect, and government standards for intervening should be the same, regardless of what assortment of adults are in the home. There are married heterosexual fathers who rape their minor daughters and there are cohabiting gay men who rape their minor sons and there are polygamist fathers who force their adolescent daughters into "marriages" with much older relatives (in the latter case, often with a government-issued marriage certificate) -- all should be ruthlessly prosecuted for what they're doing to the not-capable-of-consenting minors. They should not be prosecuted or discriminated against by government for whatever they're doing with each other with mutual consent (and likewise, government should not be interfering with private citizens, businesses, landlords, and other private organizations, which wish to discriminate against any of these groups).