i just couldn't understand why this would happen. >> mcfarland: after four months in the nicu, a.j.as ready to go home. but his recovery was far from over. >> he developed slower than full-term children. he had extensive physical therapy, occupational therapy, speech therapy just to make sure that he had every opportunity to catch up. and now he's six, and it's-- i'm now seeing his personality. i'm now seeing him. he likes to sing. he likes to dance. you know, he likes to play instruments. and it's amazing because his vocabulary took a long time. >> mcfarland: a.j.'s a happy, healthy six-year-old today. but the odds were against him when he was born. >> there are some babies that survive at 23 weeks, but these are pretty uncommon. it's usually about 24 weeks where we're talking about a realistic chance. but even at that point, when the baby's 3 1/2 months premature, there are a lot of risks. the survival is certainly not guaranteed. and there are many complications that the babies can have, both short-term and long-term. by 28 weeks, that risk does drop significantly, but it's still