You know, I had hardly posted it, when I realised someone would comment on it being all male. I don't particularly think of healers as being male, neither do I think of mankind as being male. If I were personifying mankind, I would probably take the word "he" rather than "it". For something mechanical I'd use "she"... It is not a conscious thing. I think maybe I will go for verse one as "he", verse two as "she" and verse three as "they". It would give the song a bit of dramatic development too.
Thanks for all your interest and comments so far.