Question of gender: "i gatti" is the plural of "il gatto", while "le gatte" comes from "la gatta". In Italian, the male plural form serves as a comprehensive plural. Thus when you say "i gatti", it could mean male only cats but also just cats. "Le gatte" however would mean female only cats.
The masculine form is the default in general, even when it comes to more sensitive things, such as job titles.
This is true for all or most languages which have a grammtical gender partly or completely overlapping with biological ones, and gives raises to debate (see https://en.wikipedia.org/wiki/Gender_neutrality_in_languages_with_grammatical_gender#Romance_languages).
As a language learner, you are probably given special leeway and won't offend anyone by calling them their masculine or feminine counterpart (not even cats). However, keeping in mind that using words can change how people feel and think about you, themselves, or the world is never wrong.