According to Unhindered Living, a Christian hippy lifestyle site, men are able to produce milk and breastfeed their children. How do we know this? The Bible tells us so--The Bible and Ananova.
Whatever the truth, I'm sure there are plenty of women who'd wish breastfeeding upon men.
[update: Just found The Milkmen, one mom's loong, personal search for the reality of male breastfeeding.]