I dont think Deborah was ever a mans name, since it was a female name since the old days of the Bible.
No girls name would ever become a boys name - it would never happen, since males are too intimidated by anything that is feminine.
It for the same reason that any woman can put on a mans shirt, but no man can ever put on a womans blouse.
No woman is bothered by taking on masculine names, characteristic, jobs, or traits, but men are phobic about taking on anything that is feminine.
Shirley and Beverly, used to be common mens names a hundred years ago, the most famous: George Beverly Shea, who sang at every Billy Graham meeting.
Other boys names that have pretty much been abandoned by the males. and which now are considered sissy girls names are:
Jan, Jean, Jeanne, and Gene, Francis(Francis Scott Key), Terry, Gerri, Lauren, Ricky, Gail, Cleo, Ryan, Chick, Marty, Randy, Dani and Dana, Aron/Erin, Derek, Rene, Berni, Effa, Lonnie, Jamie, Abbie, Riley, Judy (Judy Johnson), Lynn, Jessie, Gay, Sammy, Christy, Cory, Tony, Jamie, Jackie (Jackie Robinson), Bobby, Billie, Nellie, Charley, Mickey, Kerry, Johny, Frankie, Ray, and Carol(Carol OConner-Archie Bunker).