How do you make a decision when you're torn between two life dreams?

I've always wanted to take horse back riding lessons,and I've always wanted to have kids. We had to stop trying for a family via iui through a sperm bank because we had to move.We didn't have any success.Now that our finances are better,we're talking about trying again in January of 2012. I know if I get pregnant,i'll have to stop riding. I feel selfish that I'm even comparing the two,but how do you choose when two things you've wanted for as long as you can remember seem to be colliding? (for those of you that were going to suggest adoption,we live in Alabama,a decidedly ungay friendly state.I've asked CPS about adoption,and they said,and i quote 'absolutely not')