Not to make things more confusing but I will attempt to clarify a common mistake about gender in language.
The endings of a noun (or pronoun) do not determine its gender. However, in the case of normal nouns (and not pronouns) the gender can determine the set of endings used. For example: animus, -i (soul, spirit) is a masculine noun of the 2nd Declension. aurum, -i (gold) is a neuter noun of the 2nd Declension. However, the -s and -m (respectively) endings are not what makes them masculine and neuter -- they do change what set of endings you use for each declension though.
Noun gender, to the modern linguist, is quite arbitrary. I would imagine at some point it made sense to the Romans (or I should say I HOPE it made sense to them). The only way for us lowly Latinists to learn a word's gender is by memorizing the m, f, or n listed (usually in parenthesis like these) in a dictionary.
That being said, pronoun gender is an odd science because each grouping of pronouns has its own set of rules on gender. [Groupings: Personal Pronouns, Possessive Pronouns, Reflexive Pronouns, Demonstrative Pronouns, Relative Pronouns, and Interrogative Pronouns.]
Personal Pronouns: ego, nos, tu, and vos (along with all declined forms of these) have no gender. On the other hand, is, ea, id are m, f, n, respectively and each has its own set of declined forms.
Possessive Pronouns: these all take the gender of that which they are referencing and are declined like adjectives of the 1st and 2nd declensions.
Please let me know if I have raised more questions than answers! Good luck!
~~~I will apologize now for being a Yank. Please do not let me bad English grammar and spelling deter you from talking to me :D ~~~