Finnish has no grammatical gender and has never had. There is nothing corresponding to the division of nouns to masculine, feminine, and neuter in many Indo-European languages.
The same 3rd person pronoun hän (plural he) is used for both sexes, i.e. as corresponding to both “he” and “she” in English. The colloquial 3rd person pronoun se is also sex-neutral.
There is no way to distinguish between male and female by the choice of a pronoun. This often causes problems in translation and other contexts. For example, a person’s name may need to be repeated for clarity, instead of using a pronoun. Another, usually clumsier method is to use nouns like mies (man) and nainen (woman).
Although Finnish lacks gender as a grammatical category, it has a few ways to indicate the natural sex of a person or an animal with the choice of a word. As in English, many domestic animals have different words for the sexes, such as härkä (bull) and lehmä (cow). Finnish has such words even for a few wild animals, though most of them are nowadays little known to most speakers of the language, such as koppelo (female capercaillie) as opposite to metso (capercaillie as a species, also used for male capercaillies).
However, in most situations, the sex is indicated using a synthetic expression involving a word that means male or female. For example, a male bear is uroskarhu and a female bear is naaraskarhu, if you need to or wish to make the distinction. The word uros : uroksen simply means a male animal, and naaras : naaraan means a female animal. Alternatively, such a compound may have the parts in the opposite order, emphasizing the sex: karhu-uros and karhunaaras. As a synonym for uros, the word koiras : koiraan is also used, though usually not about bears or other mammals.
When referring to people, the words mies and nainen are used in a similar manner to express the sex of a person, if it is relevant. They are normally used as the first part of a closed compound, e.g. naisopettaja (female teacher). For nationalities, a compound with mies or nainen as the second part is used, e.g. suomalaismies or suomalainen mies.
The tAr : ttAre- suffix can be used to derive words for “female…” or “wife of…”, e.g. piispatar : piispattaren (bishop’s wife) from piispa (bishop). The old-fashioned inna suffix, of Swedish origin, e.g. tohtorinna (doctor’s wife), is used for the same purpose for some words, and so is the popular language ska, e.g. Virtaska (Virtanen’s wife). Most of these derivations are now mostly regarded as outdated or even obsolete. Instead of piispatar, one would normally say piispan puoliso (bishop’s spouse).
It might still be relevant and accepted in some situations to use the word laulajatar for a female singer, instead of the sex-neutral laulaja, but this is due to tradition. An actor is näyttelijä, whereas an actress can be called näyttelijä or näyttelijätär. A mistress is rakastajatar, not rakastaja, which is male only (lover). On the other hand, calling a female teacher opettajatar, as opposite to opettaja, would make you sound very old-fashioned.
Words such as pariisitar (female Parisian) still have some use, and they can in principle be derived from any country or place name. Such words are used in some forms of literature and also in sports language, where e.g. italiatar might be used to refer to a female Italian competitor.
However, the word suometar is not used, except historically as the proper name of a newspaper.
Some words like kuningatar (queen), derived from kuningas (king) and denoting both a king’s wife and a ruling queen, are an established part of the vocabulary.
The suffix tAr is normally appended to the stem of the base word, using weak grade in all forms, e.g. englannitar : englannittaren, from Englanti : Englannin. However, kuningatar, ruhtinatar, and valtiatar have exceptionally been formed by replacing the final s of the base word with the tar suffix.
There are loanwords like prinsessa (princess) containing a foreign feminine suffix, but such suffixes are not used to derive new words.
A rather exceptional word is venakko (female Russian), a colloquial old word, related to venäläinen (Russian). It is nowadays often misunderstood and used as denoting a Russian person in general.
As in other languages, some words denoting professions or positions contain a part that denotes man (or less often woman), e.g. puhemies (chairman), poliisimies (policeman). There are different opinions and practices on them. E.g., puhemies is generally used about a female chairman, too, but instead of poliisimies, one might use poliisinainen when referring to a female policeman. In official contexts, one might use the longer and somewhat clumsy word poliisivirkailija (police officer) about a policeman of either sex. Compounds formed from old compounds by replacing mies with henkilö (person), e.g. puhehenkilö and poliisihenkilö, are mostly taken as jocular and not as particularly good jokes.
The word emäntä means originally a housewife and is derived from the old word emä (mother). Yet, some professional titles ending with emäntä might nowadays be used about men, too. On the other hand, lentoemäntä (stewardess) means a female person only; for the male counterpart, the loanword stuertti (steward) is used.