1 or 2 embryo transfer?

Are you transferring one or two embryos? If you’re doing 2, what is your reasoning?

I’m still waiting for my retrieval so I have no idea how the transfers work, but I’ve heard of some women doing two. I’m older (I’ll be 37 in a few months) and the idea of twins is overwhelming, but at the same time we want more than one baby so it wouldn’t be the worst thing in the world. My doctor also suspects I have endometriosis so it’s possible that if I only do 1 it might not implant. All of my embryos will be frozen because we want them to be tested.