As far as same sex couples go there are a number of different ways that treatment can be carried out.
When we are talking about treating a female couple then we can either do an intrauterine insemination with donor sperm or we can move to IVF if needed, again with the use of donor sperm. If the treatment is going to be IVF, then it is possible to use the eggs of one of the couple and then after insemination with donor sperm, the other woman could have the embryos transferred into her uterus. In this situation it will potentially allow them both to feel more connected to the child.
In the case of a male couple it is going to be a little more complicated as there is going to need to be an egg donor and a surrogate to carry the pregnancy. This could potentially be in the form of traditional surrogacy when an IUI with the sperm of either of the guys is used, or more commonly when an egg donor undertakes an IVF cycle and the resultant embryos are transferred into a separate surrogate.
In any of the above mentioned situations there will need to be legal documents drawn up and we can point you towards appropriately informed experts.