It's not that your partner's attributes are unimportant, it's that if you are clear that you do want to start a family then this fact is rightly at the front of your mind when looking for a partner and the decision will flow from it. If you don't wish to start a family then other factors will come into play. However in the latter case you still need to include questions like whether you or your partner might have a change of mind later on, what options will remain, what retirement without children might look like, etc.