Una pene makes no sense. Also it would technically be penecillo, with a c. However, we do use polla which is akin to dick/cock and is feminine. We also say coño which means vagina and that is masculine
in portuguese we have something similar. "pênis", "pinto" and "pau" are masculine, but "piroca" is feminine.
why so many words for the same thing? good question! i have no idea!
btw if you want to know what each one means:
pênis: penis
pinto: closest translation in this meaning would be "cock" but the other, more common, meaning is "chick" as in a baby chicken
pau: literally means stick and can be used to refer to a penis. (thankfully there's also "graveto" which means stick but people don't think about a penis when they hear it)
piroca: i don't know if there is any meaning for this word other than dick or penis, and im pretty sure it's some variation of "pinto", made to sound goofier (and it seems it's feminine just because it ends with an A)
I feel that 'gender' is probably a misleading term for the languages that have 'grammatical gender', it rarely has anything to do with genitalia. 'Noun class', where adjectives have to decline to agree with the class would fit better in most cases.
English essentially does not have decline adjectives, except for historical outliers like blond/e where no-one much cares if you don't bother, and uses his / hers / its / erc using a very predictable rule. So no 'grammatical gender'.
in humans the gender can be any, even when the person has specific genitalia. so saying gender is a misleading term because it rarely has to do with genitalia doesn't make much sense to me.
so basically i dont see why not just call it gender when the pronouns given to each word in such languages is gendered
The problem is that the noun class that is used to refer to you is based on your gender. As long as that is the case, grammatical gender will probably be the most apt name for the concept.
English has the peculiarity of having two variants of the same word: "gender" and "genre" with slightly different meanings.
You could lean on it and go with genre. But just changing the word is unlikely to help much, the concept itself is deeply associated with genitalia in English culture, you'd still need to explain it.