When speaking about family members, it is not necessary to include the article before the possessive. Saying "miei genitori" instead of "i miei genitori" is acceptable.
It is only true for singulars (e.g. mia figlia), not for plurals (e.g. le mie figlie).
Yeah, I think there are four exceptions. I know plural and loro are two of them, but I can't remember the other two.
"I miei" means "I miei genitori" in Italy
Keep in mind its still considered slang even though its common.
Why is it not il Caffè? Rather than just Caffè at the end?
They always demand precise translations of the articles. If they don't have a "the" in the sentence, you shouldn't put it there (and vice versa).
When is it 'Ai' at the beginning? There was a sentence earlier that translated as 'my parents like the beer' that started 'Ai miei genitori....' so why not here?
I think this is because in Italian, instead of saying "they like it" you say something more like "it is pleasing to them" so "ai miei genitori" means "to my parents" with ai being a contraction of a (to) and i (the) :-)
Why 'bevono' and not 'prendono'?
Because it's about the verb "to drink", not the verb "to take". ;)
Why not say Mio genetori?
Mio is singular, genitori is plural. The first has to agree with the second.