I don't have a specific source but I believe that masculine names shifting to become feminine, but not the reverse, is a common thing going back at least a few

I don't have a specific source but I believe that masculine names shifting to become feminine, but not the reverse, is a common thing going back at least a few centuries. E.g. Leslie, Allison, Meredith, Lauren, Stacey were all predominantly male names until the 19th or 20th century. Often the shift seems to be due to a celebrity - the change in "Lauren" being generally attributed to Lauren Bacall, etc.