Gail is a masculine and feminine given name.
As a feminine name, it can be a short form of the Biblical name Abigail.
Gail has been used as a masculine and feminine name, and until the 1930s, was equally rare on either sex.
Between the 1930s and 1960s its use as a feminine name increased, as a consequence marginalizing masculine usage by about 1960.
[1] Alternate spellings include Gaile, Gale, and Gayle.