When does it go from an idle idea along the lines of "Wouldn't it be lovely to give a little child a home and loving family?" to looking at your finances / getting a bigger home / contacting adoption agencies, or whatever?
Some other questions:
How financially secure do you have to be?
Do they let you adopt if you, as the mother, will be working and not a SAHM?
How do you know your child wasn't wrongly taken from perfectly fit parents?