FYI: рождение is a noun in the genitive case here (day of birth)
I suppose it's because it's about choosing "one of many" days?
It's the same as the genitive "the day of birth" in English, the regular possessive construction.
How would I say this politely? Когда ваш день рождения?
да, это так )
Would "what day is your birthday?" Be correct?
I think that would be «(на) Какой день твой день рождение?»
When is your day of birth is not accepted :<
Well in English you wouldn't say "day of birth", it sounds weird.
Can any tell me if the pronunciation is right, that ж doesn't sound? Спасибо.
It's perfect Russian. And what exactly do you mean by ж ? It sounds just like it's in "genre".
Is день feminine or masculine?
It's masculine. You can tell by the fact that they used "твой" instead of "твоя" in the example.