Board Thread:Naruto Discussions/@comment-26190972-20151021201438/@comment-26369387-20151021205932

Considering that with Yin Release you can "create form out of nothingness" and with Yang Release you can "breathe life into form", it is easy to think that Yang Release is used in Medical Ninjutsu.

Also, if we look at chakra natures of known medical-nin(Tsunade, Sakura, Ino, Kabuto), all of them have Yang Release, which does speaks for itself.