CF for teh win!
No, seriously now. I'm CF and plan to get my tubes tied one day. For now, I like staying on the Pill because it helps against cramps and let's me plan my periods. And to get my tubes tied AND stay on the pill... well, there is such a thing as overkill
I like children (well behaved ones, that is), but not 24/7. I need my peace and quiet and most importantly: my freedom. I'm a 'free spirit' as others often describe me. I don't even want to own my own home for this reason! I don't like anything that ties me to a place for a long period of time, and I don't want to make a kid go to a new school and lose all their friends every three years.
I also want to be a writer. I did Steve's exercise to find my purpose in life and mine is "to create worlds". Writing is what makes me get up in the morning and it's what I would like to do all day if I could. Having to watch a child, especially a young one, will not help matters. Also, pregnancy can permanently affect the brain: just the risk of getting 'mom-nesia' alone is enough to send me running to the nearest drugstore for condoms and a supply of Plan B. There are plenty of succesful female writers who are also mothers, but I doubt I could do both and not lose my sanity. I'm just not wired like that.
Money: it's a bit of an addition to the above point, but money is a problem. Let's face it: writing is not something you should do to get-rich-quick. Though it is possible to live off your writing (and I intend to!), it often takes years before you get to the point where your royalties can cover your expenses. The lower I keep my expenses, the faster I will get to the point where I can write full-time. And let's face it: offspring aint free!
Environment: for a dominant species such as humans, there are far too many of us walking around on this planet. I see in my own country (the Netherlands) all the time: the roads are clogged, the trains are full, there is a massive house-shortage and they are already discussing building an artificial island in the shape of a tulip. The madness has to stop!