Adoption

Personally, I think that it depends on the people not their sexual orientation or marital status, but my order is:

1. A married couple
2. A homosexual couple of any sex
3. A single person of any sex or sexual orientation
4. An unmarried hetereosexual couple

The reason that I put unmarried hetereosexual couples at the bottom is that, in my opnion, there is not as much comitment.