McG. I'm note sure about your point regarding discriminations, can you clarify?

It seems obvious that smokers would be discriminated against - their choice to smoke, which they can change as and when they like, is instantly and physically harmful to the extent of being life-threatening and life-limiting for the child.

I'm not so sure about the overweight issue and I don't know of any polygamy in this part of the world. I don't really see what would preclude either of those groups, unless an overweight person was physically unable to look after children for reasons of restricted mobility or other health issues.

Stable homosexual couples, screened and pored over every bit as heterosexual couples for their suitability and demonstrable aptitude for parenting, is there a problem there?