babynames | Girls' names that "originated" as boys' names.

I know in the past there's been a lot of discussion of unisex names that are now more commonly used on girls, such as Robin, Ashley, Marion, etc. I've been interested to see when the names became more popular on girls, so I checked out the stats on the Name Voyager and this is what I found:

Shirley - In the 1890s, it was #465 for boys and #377 for girls; the dates don't go any earlier than that, so it must have been before this that it became popular on girls. Both reached their peak (for the # of babies named this, not for the actual rank) in the 1930s when it was #519 for boys and #4 for girls and not in the top 1000 for boys. It's currently #766 for girls.

Robin - First showed up in the 1930s when it was #616 for boys and #851 for girls. It became more popular on girls in the 1940s and is now much more commonly used on girls. It's not currently in the top 1000 for boys, and #943 for girls.

Ashley - Ranked #663 for boys in the 1890s, but does not show up in the top 1000 for girls until the 1960s when it was #682. It became more popular on girls in the 1970s (#140 for girls and #382 for boys) and is currently ranked #12 for girls and has not been in the top 1000 for boys since the 1990s, when it was #979.

Marion - Ranked #112 for boys in the 1890s and #74 for girls, so it was more popular on girls beginning at the end of the 19th century, and possibly before; surprisingly, the name became more popular for boys beginning in the 1970s, which is the complete reverse of what we expect for unisex names in the recent years. The name is not currently in the top 1000 for either gender and has not been since the 1980s (#993 for girls and #692 for boys).

ETA: By popular demand, I decided to go back and add a few more to this list

Courtney - Ranked #898 for boys in the 1890s, but pretty much died out until the 1940s, when it reemerged at #847. Moved into usage for girls in the 1960s when it was ranked #557. That same year, it became more popular for girls than for boys. Most recently in the top 1000 for boys in the 1990s when it was ranked #548; now ranked #190 for girls. My guess is that the name pretty much died out for boys, and started being used (uncommonly) for girls, and that it skyrocketed for both genders right around the same time, it just moved faster for boys at first since some of these boys may have had grandfathers named Courtney or something.

Kelly - Ranked pretty steadily in the 500s for boys from the 1890s to the 1940s when it started to become less popular. Moved into useage for girls in the 1950s when it was #205 for girls and #200 for boys. By the 1960s, it was #123 for boys and #30 for girls. Currently #212 for girls and is not in the top 1000 for boys (that said, I know two boys under the age of 10 named this, and another woman who is getting married next year who says Kelly is her first choice for a boy).

Stacy - Ranked #993 for boys in the 1890s, but the popular dwindled and it was not in the top 1000 again until the 1940s when it was #854 for boys. Became popular for girls in the 1950s when it was ranked #407 for girls and #589 for boys. Last ranked #724 for boys in the 1980s but is no longer in the top 1000. For girls, it is currently ranked #672.

I thought it was really interesting, because a lot of the discussions in the community tend to assume that the boys-names-on-girls phenomenon is very new, when the data shows that the names have been popular on girls (with the exception of Ashley) for over 100 years, and that, in fact, the name Marion (which most would consider to be a feminine name) became more popular on boys in the last 40 years.

Note: I know there are names I didn't look at, but there are SO MANY that are "unisex" that it would take me forever. I just used the ones that either I was interested in, or that are frequently listed when people are discussing "unisex names that became girls' names."