gender

Gender is required on apparel because sizing is gender-specific — a medium men's shirt isn't the same as a medium women's shirt. Without gender, channels can't apply the right size mapping logic, which produces wrong-size results that hurt user trust and increase returns.

The three values — male, female, unisex — are the only accepted set. "Men", "women", "mens", "M/F" all get rejected. The strict enum exists because channels apply size mapping rules per gender; ambiguous values break the mapping entirely. The strategic call: use unisex sparingly. Items designed for one gender but marketed unisex to expand reach end up shown to users with mismatched size expectations, which hurts returns and conversion. Real unisex items (oversized t-shirts, neutral accessories) are fine; gender-disguised marketing is not.

For non-apparel categories, gender is optional but populating it where there's a clear target audience helps targeting. Men's grooming products, women's haircare, kids' toys all benefit from explicit gender even though it's not strictly required.