Why not go after the causes?

[somitcw]

When the cause was stopped in young boys,
gynecomastia went away in a few months.
It may be too late to stop using them after
puberty, but avoiding products that interfere
with hormone could still be wise.  If sales
drop enough, the products could be changed?

See the Safety sections of:

http://en.wikipedia.org/wiki/Lavender_oil
http://en.wikipedia.org/wiki/Tea_tree_oil