It's clear (to me, anyway) that Frankie Lymon was a big influence on little MJ's mature, soulful vocal delivery, especially in the earlier days. The Teeneagers were before his time, but no doubt the musicians at Motown helped to mold him and the J5 into that vein. Check out some Frankie Lymon clips here:

http://www.youtube.com/wa...ie%20lymon
http://www.youtube.com/wa...ie%20lymon
http://www.youtube.com/wa...ie%20lymon
http://www.youtube.com/wa...ie%20lymon
http://www.youtube.com/wa...ie%20lymon

MJ was a litle edgyier and took from a wide range on influences, but the ballads were "Frankie" all the way, especially in "Who's Loving You".

"I'm Not A Juvenile Delinquent"