This whole area is such a minefield. I've been reading along with this thread but haven't commented yet because I can't really figure out where I sit!
On one hand, I had to do IVF to conceive my DD - I spent some time not knowing if I'd ever get pregnant so I see my DD as my greatest blessing, and I would feel exactly the same had she been a boy. I can't really imagine why anyone would willingly subject themselves to the whole awful IVF process if they didn't need to. But then if I had the option of knowing the sex of my remaining embryos, when it comes time to try for baby number two, I'd probably ask for my girl embryos to be put back first - mainly because I have an awesome relationship with my sister and I'd love for my DD to experience the same thing, plus I want to have the chance to reuse her gorgeous girly stuff she grew out of too quickly! But if they didn't work, I'd happily try the boy ones too. Obviously I don't have that option so I won't be doing that and I'll be overjoyed if I'm ever able to bring a second baby into the world, regardless of gender. But then if I think it would be OK for me to do it because I'm already doing IVF anyway, why then wouldn't it be ok for someone else to do IVF for that purpose? It's their body after all and if they want to go through the whole process why should I stop them?
I think it's the willingness to discard perfectly good embryos that doesn't sit right with me. To me, it's so hard to create those little embies in the first place, I can't imagine just discarding unwanted ones. But I don't think forced donation of unwanted embryos is right either.
This makes my brain hurt. I'm so glad I'm not the one responsible for making this decision!!