We know lots of people who have adopted. One couple went to Romania, and was appalled at the conditions of the orphanages there. They brought back the most adorable little undernourished 8-mo.-old girl and named her Lillian. She's two years old now, and the delight of everyone. She's in perfect health now, and her adopted father has since entered medical school as a result of his experiences.
Another couple of friends adopted a sister and brother from Russia. They were 1 and 3 when they adopted them, and the little girl just started school this year. Smart kids.
Another friend adopted a baby girl from China three years ago. Our friend is divorced, semi-retired, and has a 23-year-old daughter. She said she couldn't imagine any better way to spend her 50s and 60s than raising this child.
And the stories go on and on...
From personal experience, I can say there is nothing like the experience of being pregnant...it is wonderful. I was the world's happiest pregnant woman before my son was born...I was so elated that I woke up singing songs every day!...I was absolutely insufferable.

But if being pregnant is not a wise thing to do for you because of physical problems, I would say skip it. It doesn't really last very long anyway. It's more important that your child have a mother in the best possible health she can manage.
It's being a parent that counts...not how you get there.