Why doesn't English had feminine and masculine nouns?
Why does Spain, France, and Germany all have masculine and feminine nouns, but the UK and the USA somehow got left out?
English does have nouns with gender when the sex is obvious, such man/woman, lion/lioness, bull/cow, etc. However, all other nouns are neuter. This is probably because most of English comes from French or German and the two languages assign the opposite gender to most things.
Old English did have gender nouns, but the use mostly phased out, and gender agreement mostly doesn't exist (some exceptions exist with words like blond/blonde ("she is a blonde" vs "he is a blond") or obvious ones like actor/actress).
Maybe gender will phase out of other languages too? After all, why should a house be female? The less you have to know about differences in the things involved in the language, and can rely just on the language itself, the better the language is going to be at getting ideas across. Take for example:
"These two girls are sisters" - from this statement, you can pretty much work out they the two girls referenced must have the same parents; their relationship to each other is 'sister'. But -
"These two girls are mothers" - you know this must be different from the statement above, as the two girls cannot be each others mother, so you know the statement must be saying that they both have children.
The language has failed at this point, and requires your knowledge of the terms for you to be able to understand what has been said. Relying purely on the language would lead you to believe that both girls gave birth to each other, or that both girls in the above statement have siblings but aren't related to each other.
Having to know that a house or a table is female, or a dog is male, is similar to this. Knowing the language should be enough to be able to use it for idea conveyance, but it's not, you need to know all these extra things about each thing you'd use the language for, that's unrelated to actual information about the noun. I think it's definitely a good thing that English has lost this.
Because you can generalize using the and it. But we do use "his" and "hers" if it makes you feel better.
Oh, don't worry about it. It just makes English easier.