I'm not convinced that because Christians believe that God loves them, that this makes them love - oh yes I think it helps to have been loved by others, but ISTM that Love is something humans do innately.

I think that this is slightly overstating things, Martin.  Having taught in a variety of places, and worked with a variety of adults, I would suggest that without the 'have been loved by others' (and that doesn't necessarily have to be parents) someone finds it very hard to love someone other than themselves.