reporter: a baby arrives and a song is sung. reporter: another baby and again singing. i watch them grow reporter: and again and again. reporter: by this time something like 6,000 deliveries, 6,000 vocal performances brought off by a man whose name sounds like a 1960 s pop lyric, carey andrew-jaja, obstetrician. to the family this is special. reporter: he works at women s hospital at upmc and has been singing to newborns since his training days because one of his teachers was also a singing obstetrician. he asked me to continue the tradition and i have done it ever since. happy birthday reporter: so much so that new mothers would be disappointed if dr. jaja had not sung when her daughter was born. first happy birthday. reporter: look at these faces. sure some science that says