I'm not sure why you think you can't have a healthy baby after RNY. There are several people on here (me being one) that have had healthy babies. There's a few on here that have had healthy babies and they were less then a year out. Of course it's better to wait at least a year, but things happen for a reason. The baby will take what he/she will need first then you get what ever is left. I know that with my pregnancy I gained 23 lbs which is a "normal" weight gain. Most doc's want you to gain no more then 25-30lbs. My baby was 7lbs 7oz and 21 inches long. Came out pink and screaming.
Best day of my life!
So if you are worried about a healthy baby after RNY you shouldn't be there are pleanty of little ones that have been born around here within the last 1 1/2 years and they have all been healthy babies.
Good luck to you on whatever you decide to do. Keep coming back here because there's lots of info to be had.