First, why does the tax man need to know what genitalia your children have and are you comfortable with that? Second, what do you consider people with neither or both kinds? Subhumans ineligible to be dependents?
> Male/female is determined by chromosomes, either XX or XY.
This isn’t true legally (where “sex” is really an ascribed gender assigned at birth and possibly updated later for a variety of reasons) or medically (since an individual with a 46,XX karyotype can be male or female medically, as can an individual with a 46,XY karyotype.)
Ah. Totally relevant this piece of information when tax is concerned. /s
Seriously however, any link to where this is specified in the way you claim it to be? How does it see SRY gene disorders? If your child is a daughter to you but technically has XY, will the law mandate you to declare her as a son? etc.