Gender Marker (Medical / Governmental) Regex for Python

What this pattern does

This page provides a comprehensive, battle-tested regular expression for matching gender marker (medical / governmental), ported and verified for Python. Identity and credential patterns need both correctness and safety, since they're frequent targets for adversarial input. The snippet below is ready to drop into your Python project — whether you're validating in a Django view, a FastAPI endpoint, or a standalone data processing script.

Python Implementation

# Gender Marker (Medical / Governmental)
# ReDoS-safe | RegexVault — Identity & PII > Biometric & Physical

import re

gender_marker_medical_governmental_pattern = re.compile(r'^(?:M|F|X|O|U|N|NB|MALE|FEMALE|NON-BINARY|UNKNOWN|UNSPECIFIED|PREFER_NOT_TO_SAY|INTERSEX)$')

def validate_gender_marker_medical_governmental(value: str) -> bool:
    return bool(gender_marker_medical_governmental_pattern.fullmatch(value))

# Example
print(validate_gender_marker_medical_governmental("M"))  # True

Test Cases

When to use this pattern

This pattern is drawn from the Identity & PII > Biometric & Physical category and carries a ReDoS-safe certification. That matters for Python developers because particularly important in Python web servers where CPU-bound regex operations can stall concurrent request handling. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Technical Notes

ICAO uses M/F/X for passports. HL7 FHIR uses M/F/O/U/N codes. Government documents vary: AU allows X (non-binary), UK driving licence adds a 5-month offset for female, CA federal documents allow X. The X gender marker is now recognized in many jurisdictions.