Gender isn't specified when booking a BA airline ticket. A title is specified but that title can be Dr, Professor, Captain, Reverend, etc, which give no indication of gender.

Meanwhile, even if you try to guesstimate the gender from the title, that doesn't tell you the amenity kit preference with complete reliability.

So no, BA does not know how many "male" and how many "female" amenity kits will be needed. The only reliable thing to do would be to measure usage and then load enough to cover the extremes (something like enough amenity kits to give 80% of the cabin one or the other).