I am a Trustee for an organisation and have recently reviewed a legal document that describes protected characteristics including age, ethnicity and then gender. I have argued to the Chair that the wording needs to be changed to sex. He is asking me to provide arguments to justify the change. I am not a lawyer and I dont think it is particularly appropriate for me to go in arguing the law as if I am. My organisation is independent but falls under an umbrella org. The legal document has come from the umbrella organisation and I think this is part of the reason he doesnt want to dispute.
Any ideas on how i can more eloquently than I have so far managed persuade him that this is important. TIA.