As far as adoption vs. bio, our family has been created by adoption. Not because we didn't want bio kids, but because we believe this was God's plan for our family. And I can't say I have any complaints with his work so far.
But I would never presume to think someone who wants biological children is being any more selfish than any other parent. I have studied long and hard on this - philosophically speaking - and have come to the conclusion that wanting to be a parent of any kind comes with a great deal of selfishness - "I" want to love; "I" want to give; "I" want to teach; "I" want to help; "I" want to save.
We've heard so many people say what a wonderful and selfless thing we did in adopting our son and frankly, I find those comments well meaning, but embarrassing, because it's just not true. He has given us so much more. Our son is the selfless one. For us, HE is the real champion in adoption.