I think this is generally so, in most languages, and my theory is as follows:
In a patriarchal society (as most are) you speak of your ancestors as forefathers, it is the men who go to war and they fight for their fatherland.
(Yup, the word exists in English as well, dating back to the 12th century (according to Merriam Webster http://www.m-w.com) , which is why it probably isn´t widely used - possibly the Germanic influence in English, as a haphazard guess. Mother country (and motherland) are younger, however, if I´m not mistaken, the normal term today is native country.)
So here we get Vaterland, patria, patrie, isänmaa, otechestvo, fädernesland…
In the meantime, the women stay at home, and it is (mainly) from them that the children learn their language - their mother tongue, äidinkieli, Muttersprache, lengua materna, langue maternelle, lingua materna, modertaal, modersmal, mhtrik glessa (inaccurate transcription of the Greek word with the same meaning)… (not in Russian, though - rodnoi jazik, just as rodina, come from the word for birth)
(I know this is simplistic, but the native language is something psychologically associated with your home, not your education, warfare or whatever.)
But wait, there´s more! As soon as the native country is not seen as the land you are fighting for, but rather the place you come from, the place where you felt secure, and often - if you have emigrated - miss, it is associated with the caring love of a mother.
I don´t know about mother country, but in other languages you get things like la madre patria, matushka Rossija (Mother Russia; actually, matushka is a diminutive, affectionate form of mat, mother), Moder Svea, Mutterland - and for all you German speakers, think of Bert Brecht´s “Deutschland, bleiche Mutter”. This is very often in the context of war, when the country is crying for her lost sons.
(England is a “she”, by the way…)
(exception here: Finnish does not assign a sex to words or concepts, not even in the very limited way English does this (the sun is a “he”, while the moon is a “she”) - it doesn´t have the personal pronouns (he/she) for that. So the only way of expressing this would be via äidinmaa, which, however, could only be used to mean the country your mother came from.)
I think there´s some pretty interesting studies in comparative linguistics on this, but I venture to say the psychological component I´ve mentioned here is quite strong - after all, we coin words according to our perception of the world and our feelings.
(Though I do quite often wonder what exactly the old Germanic peoples were thinking when they made “carrot” feminine and “apple” masculine… not to mention “girl”, which is neuter…
)