Would it be correct to say that "en katt" is a male cat and "ei katt" would be a female cat (likewise "en hund" or "ei hund"), or are all cats male (grammatically speaking)?
Generally speaking, the grammatical gender of a noun does not reflect the biological gender of the animal it refers to. So you can refer to a male cat as "ei katt", or a female cat as "en katt".
However, we actually have a separate word for female cats, so it's a tricky example:
en/ei katt = biologically gender neutral, no matter whether you choose the feminine or masculine form.
ei katte = a separate word that technically only refers to female cats. Not seen much in writing.
I accidently put a kat and a dog... At least it accepted it for my terrible english :)
Always having difficulties to differentiate "det er" and "de har" when I hear it ...
I put "én hund" because she seemed to be stressing the "en". Apparently, that wasn't what she said (though it was accepted)
When you use an accent on the word én, you change it from the indefinite article "a" to the number "one". It's not wrong here.
To do the same with neuter nouns you write "ett" (one) instead of et (a/an).