I've been rebuilding the dataset behind a breeding calculator I maintain (disclosure: it's mine, link at the bottom, and the data is free to download), and I hit a pair that broke my code. Sharing because I think most tools have the same bug.

Katress + Wixen produces two different Pals depending on gender:

Female Katress + male Wixen → Katress Ignis Male Katress + female Wixen → Wixen Noct Every other special combo in the game is an unordered pair — the two parents can be either gender and you get one fixed result. This is the only exception. I checked the other ten variant Pals (Jormuntide Ignis, Faleris Aqua, Frostallion Noct, Blazehowl Noct, Leezpunk Ignis, Pyrin Noct, Lyleen Noct, Gobfin Ignis, Suzaku Aqua, Elphidran Aqua) and none of them care about gender.

Why it matters: breeding datasets store combos as {parent_a, parent_b, child} with no gender field. So this pair appears twice with the same two parents and two different children. Any code that keys on the sorted pair keeps whichever row it read last and silently throws the other away. On my site that made Wixen Noct look completely unobtainable by breeding. If your calculator tells you one of these two can't be bred, that's why.

Two more things I found while checking:

Panthalus and Astralym can't breed at all. The game files contain Panthalus + Panthalus and Astralym + Astralym rows, so datamined datasets include them and some tools present them as breeding true. In game, Panthalus is too large to use any base facility including the Breeding Farm, and Astralym is the only Pal a player can't obtain at all — it's the Sealed Sanctum tower boss and it's flagged uncapturable. I've seen at least one popular calculator tell people to "catch your first Panthalus in the wild", which is wrong twice over: no wild spawn, and it's the Echoing Flute encounter on the Deserted Islet.

A self-pair row doesn't mean a Pal is unbreedable — this one was my own bug. X + X → X marks a Pal that breeds true, so I treated every Pal carrying that row as catch-only. But Relaxaurus Lux and Mossanda Lux carry it alongside a real combo (Relaxaurus + Sparkit, Mossanda + Grizzbolt). I was serving a "you can't breed this" page to two Pals that breed fine. It's 26 truly catch-only Pals, not 28.

Sources I checked against: palworld.wiki.gg, game8, paldb.cc, palworld.gg.

I've put the corrected dataset up as free JSON and CSV with no key and no rate limit — if you're building anything, take it: www.palworldonline.net/data

If you think I've got any of this wrong, say so. Game updates move these tables and I'd rather be corrected than confidently stale.