According to Wikipedia, Gail was used equally for males and females until about 1930, after which its increasing use for females marginalized its use for males by about 1960. Some examples of males with this name are: Gail Borden, American inventor, 1801-1874; Gail Borden, American figure skater, 1907-1991; Gail Bruce, American football player, 1923-1998; Gail Goodrich, American basketball player, born 1943; and Gail Halvorsen, American Air Force pilot, 1920-2022. Actor Craig Stevens of Peter Gunn fame, 1918-2000, was born Gail Shikles Jr. (I'm sure the male name is not short for Abigail and surely the female name is not necessarily either. Perhaps this is really two names with separate origins.)
Wikipedia DEFINES this name as UNISEX.
https://en.m.wikipedia.org/wiki/Gail_(given_name)
https://www.behindthename.com/name/gale-2