...but you asked, so I'll offer.
Don't do it. Please try to think beyond your own desires in this. There are too many humans on the Earth. I say that not as a Birkenstock wearing dreadlocked earth muffin but as a professional ecologist. If EVERYONE were responsible enough to step back and reflect on whether the world would be a better place with more humans or with fewer, we might have some hope for saving our world from drowning in our waste or sputtering out from our over consumption. Let me remind you that reaching human carrying capacity will not be an abstract event-- it will be a time of misery without parallel in human history. Everyone with the capacity to decide whether to have more children has a say in determining the kind of world their offspring will inherit.
Do you know "The Tragedy of the Commons" by Garrett Hardin? Here's an HTML version if you don't:
http://dieoff.org/page95.htmIt summarizes the issue better than anything else I've seen. The tragedy is that when anyone exploits common resources for their own reasons, the benefits accrue to them but everyone else bears the costs. Nowhere is this more true than in human reproduction. When everyone chooses to serve their own interests, everyone loses.
Truth in advertising disclaimer: I'm 50, have a lovely daughter, and had my vasectomy 2 weeks after she was born, 25 years ago. I hope you won't think my advice too presumptuous.