If a name that is traditionally male, ends up being used more for girls, then they can fall out of usage for boys.
That's what happened to Ashley in the U.S., as once it became a top name for girls, it rapidly all but disappeared for boys.
I think it's a real shame when that happens, but once people start seeing a name as being a girl's name, it puts parents of boys off.
However DH and I are considering Elisha for our third child, if we have a boy, because traditionally it's a Jewish male name. It's used more here in the UK for girls, as a variant spelling of Alisha, although the alternative E spelling isn't widely used. Elisha is also used for boys here, but even less than it is for girls.
Despite the fact it's not common for girls, a few (non-Jewish) friends have reacted in horror when we mentioned we might use Elisha for a boy, as "it's a girl's name." They were soon put right.
If we do have a son, he may be Elisha, he may not. If we don't use it, it certainly won't be that we've been put off by the fact it's used more for girls, it'll just be that we've found another name we like better!