I think one big consideration is that all pregnancy carries risk of loss of reproductive organs. What if something is to happen and you can never have kid of your own in the future? Would you be okay with taking that risk? Another consideration is the physical aspect of getting pregnant itself: the physical demands, hormonal changes, mood swing, morning sickness etc. There is a big difference between jumping into something irreversible for 9 months knowing what to expect (somewhat) and not knowing anything.