In Arbor, there are 4 options for setting a student's gender - Female, Male, Not Known and Not Specified. These options have been outlined by the DfE in the DfE's Complete the school census guidance.
If a student's gender hasn't been recorded, or has been set as Not Known and Not Specified, the gender will not be output in the census.
It will not flag an Arbor error, but you will still see the DfE error Error 1610. Please see this guidance for what to do if you get this error: Error 1610
Please note: You won't be able to export CTFs of students unless they are marked as Male or Female.
We are also actively considering ways to make the recording of gender identity and pronouns in Arbor more inclusive while making sure that the way gender is recorded in Arbor is still compatible with censuses. The DfE is also investigating how to improve the way they collect data, so if you have any feedback, please direct it to the DfE.