This is an interesting issue in plant selection that I hadn't previously realized. I'm not sensitive to pollen, at least not in the amounts I've so far encountered, but have allergy sufferers in the family, so do understand how debilitating it can be. Realizing that allergens is the alternative makes the debris on the ground from female trees much more bearable :-)

Karin L

Here is a link that might be useful: Story on use of male clones as street trees