I haven't heard of "man-made"latex, where did you see or hear this I would
like to find out more info for my program I'm putting together. They might
be trying to say man-made rubber products which use that new less allergic
material called,guayule which has fewer proteins and comes from a shrub.
This was from Sandra Holmes, Looking out for latex, Science and Children Vol
36 no 5 pp 21-24, 52 , I found it off one of the web sites.

Let me know if this helps

Sharon