Not your problem, you say? I don't mean the problem of wandering into the wrong restroom. Wait until you undertake to study one of the world's many languages which arbitrarily assign genders to inanimate objects. This includes most European languages (English being the most prominent exception) and others besides—Arabic, for example. Swahili has "noun classes" which work like a multivalent version of gender.
I have heard that French schoolchildren, for example, can predict with uncanny accuracy the genders of objects they have never seen before. This seems hard to believe (what about the case where two different words denote the same object but have opposite gender?). And by what possible logic is a spoon masculine, a fork feminine, and a knife neuter (as is the case in German)? Another argument against the inherent character of grammatical gender is the lack of consistency across languages: for example, "the moon" is la lune (feminine) in French but der Mond (masculine) in German.
Some languages, like Russian, or Arabic, make it fairly easy to predict the gender of a word, not by the nature of the object but by the form of the word (does it end with a?). Others, like German, have essentially no connection between the form of a word and its gender. In such cases we have no alternative but to remember the gender of each word.
This is a perfect situation in which to apply the techniques of memory training, as I have previously described. The key is to use vivid mental images to impress the gender of an object on the mind.
For a language like French, or Italian, with (only) male and female genders, an obvious approach suggests itself: visualize the object with a sex characteristic: a phallus for masculine objects, a large pair of breasts for feminine objects. (To forestall an avalanche of hostile comments, let me declare that I have nothing against small-breasted women—this merely reflects the principle that vivid, exaggerated, sexual, and even scatological images stick better in the mind).
Once you get into more than one language, you need a distinct set of visual tags for each to avoid confusion. For that matter, some languages have more than two genders: German, Russian, or Sanskrit have three, and Swahili has sixteen (though sadly, these do not reflect sixteen distinct varieties of human sexuality—that would be fun).
Let's take German as an example, which has three genders. How about the tags chocolate, vanilla, and strawberry to represent the three? Chocolate is feminine and vanilla masculine, of course (because that's yin and yang), which leaves strawberry to be neuter. Eventually, you'll need to remember these three on your own.
So let's take lists of nouns of various genders:
Masculine: Mond (moon), Hut (hat), Brief (letter)
Feminine: Sonne (sun), Jacke (jacket), Wand (wall), Maus (mouse)
Neuter: Haus (house), Hotel (hotel)
We could certainly go with longer lists, but this post is getting long enough as it is. The conclusive step is to form a vivid mental image linking each object with the appropriate flavor.
Start with moon and vanilla (masculine). Picture yourself eating a vanilla ice-cream cone, only the scoop of ice cream is actually a miniature moon. There's even a tiny spacecraft landed on it with astronauts waving a tiny flag, while the tiny command module buzzes around your head like a fly.
Now hat and vanilla: You are wearing a hat made of vanilla beans. Make sure to see it in your mind's eye.
Letter and vanilla: You receive a letter printed on vanilla ice cream. You struggle to read it before it melts.
Sun and chocolate (feminine): The sun in the sky is a huge ball of chocolate. The rays are covering you with a brown, sticky coating.
Jacket and chocolate: You are wearing a jacket made of chocolate bars—a little gooey, but oh so stylish.
Wall and chocolate: The wall of your room is an enormous chocolate bar, still in the wrapper.
By now you see, I hope, that it takes no special creativity to come up with these images. There are a few standard tricks.
Mouse and chocolate: You open a chocolate bar wrapper, and a mouse scampers out.
Now house and strawberry: Imagine returning home one day and finding your house has transformed into a giant strawberry, still with doors and windows.
Finally, hotel and strawberry: You are waiting in line to check in at a hotel and you notice all the other guests are giant ambulatory strawberries, each holding his or her suitcase.
Now it's quiz time. Keeping in mind the code (chocolate=feminine, vanilla=masculine, strawberry=neuter), what is the German gender of each of these words?
With practice, you will find this works as well for a hundred words, or five hundred, as with the nine given here.
An alternative way to select a symbol to represent a particular gender (or other grammatical categories) is to pick one example word from the class—let moon represent masculine and sun represent feminine, for example