BOSTON (AP) -- Boston Mayor Martin Walsh is threatening to boycott the St. Patrick's Day parade unless organizers allow a group of gay military veterans to march, joining New York's mayor in protesting parade policies on gay groups. Walsh, the son of Irish immigrants, said Thursday he's been trying to broker a deal with the city's parade organizers to allow a gay veterans group sponsored by MassEquality to march in this year's parade. He said allowing gay groups to participate is long overdue. "It's 2014 - it's far beyond the time where we should be even having this discussion because...