Can diapers make baby legs like o legs?

It's my understanding that nearly all babies are somewhat bowlegged and that it gets better as they mature and start walking, but it can't hurt to get him checked out.
My son had hip dysplasia as an infant and had to wear a special harness for about two months. Because we caught it early he was cured, but children who are not helped at an early age sometimes face very painful surgeries to correct the problem.
You child should be getting regular checkups anyway, so ask the doctor, he/she can either help the baby if he needs it or ease your mind by re-assuring you that the boy is fine.