I've never had any interest in having kids of my own, but I would definitely be open to adopting or helping to raise a partners children. (I could be a step-dad). As others have pointed out, there are lots of children in the world that need to be adopted or placed in foster care, and I would much rather raise a child that needs a new chance at a good life than have a child that matches me biologically.
I think a big part of this is that I have pretty severe scoliosis, and went though several surgeries and years of physical therapy. There is a possibility that it could be genetic and I wouldnt want to take the risk of passing it down. Not to mention the additional issues that I would have if I ever became pregnant (not that I would ever consider it, but I knew I never wanted to carry a child before I realized I was trans.