Honesty compels me to admit that I also expected not to be surprised by the female side of the graph, and was quite wrong (I got 4ish).
In hindsight, I realize the error I made is that even if I have an above average vocabulary, there is still going to be the extreme outliers of gender-connected words that I shouldn't expect my vocabulary to overcome. It may well be the case (and I'm serious here) that there's only another dozen or two words "female words" that I wouldn't recognize. I certainly doubt it runs for another few hundred words. But it shouldn't be surprising that there the extreme outliers are things I have entirely missed.
For instance, I knew what a doula is... but only by the skin of my teeth, so to speak, by overhearing my wife discussing it with other women at a very specific time in our lives that has only happened a limited number of times. If it had so happened I'd whiffed those windows of perhaps a few minutes total in my entire life, I'd still not know.
Femtosecond, by contrast, heck I've seen that hundreds of times easily. My wife has the requisite science training to know what that is, even if I'm not sure if she's ever used it. As it so happens just a couple of months ago I used "thermistor" in front of her and had to explain the word. She understood the concept just fine (again, had the requisite science training) but was not familiar with the word. Perhaps a bit ironically, it was in the context of describing how to fix kitchen temperature probes that were misreading.
(Since that may make someone curious, they can misread if water makes it down to the thermistor part. You can fix it by leaving it in a 200 degree oven for a while. Protip: The probe end goes in the oven, the plastic end stays outside. A, err, "friend" of mine can attest to the fact that if you cock that up through sheer idiocy, it may still work afterwards, but the plastic end certainly gets an exciting new modern art look.)