If, as it is written in Oxford Dictionaries, 'it' can be used to identify a person, 'it’s me', 'it’s a boy', why are 'she' and 'he' still used and, furthermore, why are people still discussing as to whether they should be replaced with the singular 'they'?
If any, let us use 'it' then, no?
Under a different point of view, do you, expert minds of EL&U, think that the use of 'she' and 'he', the last barricade of gender in English, is declining and that 'it' is taking their place?