Dean Peterson has heard the snickering.

His 17-year-old son "keeps quiet" about his father's new obsession, and when his 15-year-old son proposed following in his dad's footsteps, the principal at the boy's school warned that other students might pick on him.

But the 6-foot-tall, 250-pound mail carrier from Lacey, Wash., doesn't worry about anyone questioning his virility, or ogling his bare knees. He just wants to feel as free as a woman wearing a skirt.

"A lot of people think I'm crazy," said Peterson, 48, who became a mail carrier after retiring from the Air Force eight years ago. "This is important to me - I just want to be comfortable. I just want the option."

As some 10,000 mail carriers gather in Boston this week for the 66th biennial convention of the National Association of Letter Carriers, Peterson is on a one-man mission to persuade his colleagues to approve a change in their strictly regulated uniforms. He has proposed a resolution to allow mailmen to wear kilts, which he calls a Male Unbifurcated Garment, or MUG.

Over the past few weeks, he says he has spent the $1,800 he received as part of the federal government's stimulus package to send about 1,000 letters and photographs of a mockup of the new uniform to postal union branches in every state, as well as Guam and Puerto Rico.

"MUGs are worn all over the world, and have been for thousands of years because they are comfortable," he wrote to fellow mailmen. "Unbifurcated Garments are far more comfortable and suitable to male anatomy than trousers or shorts, because they don't confine the legs or cramp the male genitals the way that trousers or shorts do."

He argued that pants can cause sweat rashes and added, "Please open your hearts - and inseams - for an option in mail carrier comfort!"

Peterson's efforts have already attracted support. During the spring, similar resolutions calling for mailmen to be allowed to don kilts passed at letter carrier conventions in Washington and Oregon. Women can wear skirts.

Paul Lunde, who promoted the resolution in Oregon and has worn kilts on St. Patrick's Day, Halloween, and occasional Saturdays when his supervisors aren't paying attention, said that expanding the uniform choices would be a way to express his Celtic heritage, just as Jewish postal workers are allowed to wear yarmulkes.

Some of Lunde's co-workers have accused him of cross-dressing. Then there are the inevitable, sophomoric questions: "What are you wearing under there?" (He and Peterson insist they wear underwear.)

"They're mostly ribbing me, but occasionally there are people who appear to be offended," said Lunde, 38, who has delivered mail in Salem, Ore., for nine years. "I say, 'Show me a picture of Jesus in slacks, and I'll consider it.' " He's usually portrayed wearing some kind of long robe, Lunde added.