In many languages, nouns have gender, that is the noun is considered to be feminine, masculine or neuter (Latin for neither, not masculine, also not feminine.) The gender of the noun affects how other words relating to it are altered.
As far as I can tell, Chinese nouns do not have gender.
But Chinese has 她，他，它。
Are these three present in old Chinese, or are they a more recent addition to the language?
The characters 她 and 它 exist in old Chinese, but they were not third person pronouns and were not pronounced "ta". 她 used to be the same as 姐，meaning mother, while 它 was the original form of 蛇（snake）.
Using 她 and 它 as pronouns is indeed a rather recent development, mainly by the cohort of May Fourth Movement as a way to mordernise Chinese and make translation of English works easier. The usage of 她 as female third person pronoun was suggested in 1917-1918 by poet Liu Bannong(刘半农). Around the same time, 伊 (yi, female pronoun in the Wu dialect) was also commonly used as female third person prnoun, but gradually fell out of favour. I'm not exactly sure when and how did the 它 begin as a pronoun, some sources suggest it's the same as 她。
他 assumed its current form during Libian (隶变) 2nd Century BC, its original form was 佗(burden). It probably was populoarised as a pronoun during Ming dynasty (14th century).
