Have you talked to him about why he doesn't feel ready and perhaps why you both haven't decided to get married yet or buy a house or do any of those things he might feel are pre-requisities? I don't think you have to be married or own a house to become good parents, but the reason why you haven't done those things first might matter. If neither of you believe in marriage and don't plan to do it any way, or you're renting because you're saving money or have other goals that owning a house would get in the way of, that doesn't mean you need to postpone having a child together. If you aren't doing those things because one or both of you doesn't feel ready to make that sort of commitment to a long-term relationship, that's something entirely different, if you see what I mean.
We were married when we decided to have our daughter, but only just (I got pregnant about 8 months after our wedding and I was 31 at the time). Us personally, we wanted to be married and that seemed like the logical first step to starting a family with all the legal protections that come with it, plus I'm not a British citizen, so before we went down that road, we wanted to make sure I had some legal ties to settle here permanently because we didn't want our family to be split up because my immigration status wasn't assured. But we didn't own a house and still don't (our daughter is about to turn 4 now, so that was 5 years ago). It wasn't important for us and we wanted to be in a different financial and professional situation before we made that sort of investment. I was working towards a PhD and my husband was starting a business, so we wanted to wait til our business was profitable and I had a new job and a good salary and we wanted time to save some more money, so we could put a large deposit down and have a very small mortgage, which is what we've been able to do by renting.
Basically, if there's good reason why you've both decided you don't want to get married or buy a house first, then it shouldn't be an obstacle, but if either of you just doesn't feel ready for the commitment, I think you need to talk about that more. Houses and marriages are such minor commitments - and so much less work and stress on a relationship - than having a baby. I definitely think it's not realistic to expect to wait 5-10 years given you have PCOS and maybe talking more about that, bringing him along to meet with your doctor to discuss it, etc. might help. But maybe it sounds like he's saying he's not ready to make a number of longer term commitments and I think I'd want to talk about that before you get ahead of yourself planning for a baby. That's not to say that I think anyone needs to be married to have a family, but if you do want to be married, then you have to work out why you aren't doing that first, if that makes sense? That might get some of the answers as to why he wants to wait.
