The month of may was named after a MALE god (Maius), so are you saying May should be a boys name? Same with July and March.
Uh, okay. Good to know, although I think May is actually after the goddess Maia. Maia or Maius, it's debatable enough that the arguement would be essentially pointless. I never said anything about origin, something generally as unimportant to me as a name's literal meaning. I'm talking about usage, such as how the name has been used in my nation over time. For example, April has been on the SSA 1000 list since 1939 for girls, no statistically significant usage for boys or August on the boy list from 1880 on with no significant usage for girls. My question was whether or not the name's usage matters to you at all in assigning gender to a name. Sorry if I was somehow unclear.
I'm aware that Christian and Julian were used for boys in the middle ages, as well as Jordan, Anna for boys, and others. For me, this is not meaningful because I'm also aware of how the names are used now: Christian (b-22), Julian (b-66), Jordan (b-45, g-100), Anna (g-25). Like you say, names change over time. To me, Jordan retained its unisex identity. Christian, Julian, and Anna did not.
If your criteria is based upon whether or not a name contains clearly masculine or feminine sounds, how do you classify names such as Ezra or Elijah? Do they qualify as unisex, or even feminine, since they conceivably contain feminine sound markers?