Gay and lesbian couples who do surrogacy or IVF or IUI are not infertile, so no, it's not a fertility issue...it's a 'I don't have an opposite sexed partner to make a baby with' issue.
There's a lot of differing opinions on the use of IVF and surrogacy for any person regardless of sexual orientation.
As a feminist, my positions regarding gay and lesbians as parents are pretty common - LGB couples have every right to be parents and I don't see why they can't be as good or as bad of parents as any straight person.
Now, when you get into surrogacy, I don't think gay or straight couples should engage in it, particularly commercialized surrogacy as it so clearly exploits women and commodifies our bodies. Not all straight couples who use surrogacy are infertile - some just don't want to be inconvenienced by a pregnancy (see celebrities).
Egg selling puts health risks on women and exploits young women's naïveté about motherhood and long-term consequences, and I'm opposed to it, especially after my 15-yr old was sent ads about 'donating her eggs for a trip to Paris'.
I personally know lesbian couples and single women who have used donated sperm. I think there should be better regulations on that industry to prevent abuses, but no man is at a health risk by selling his sperm, so it's quite different from egg selling.
Brandy Carlise is a good example of a lesbian woman who had children w/ her wife and used a good friend's sperm, who is active in their children's lives. This seems like the best solution IMO and what I'd want if I were a lesbian...co-parenting is something that can benefit children because all children have a right to know who their parents are, and, if possible and safe, have a relationship with them. One thing to note about Carlisle's wife - she wanted to carry Brandy's embryo, but she had a very awful pregnancy as a result, which is a risk when a woman carries a baby not genetically her own. To me, this is an example of an industry that failed to counsel these women about the risks. They both acknowledge they'd have carried their own babies if they'd known.