Date of Birth Missing from New User Attributes

When creating a new user via the API why can’t their date of birth be submitted as part of the user attributes?

Any update on this? Any reason it can’t be added?

I’ve just started using the create ‘User’ calls too and have just gone to set the ‘Date Of Birth’ to find it isn’t available. Why would you leave it out given it’s prominent in the ‘Edit User’ forms on FreeAgent.com???