Chance per egg of inheriting all 2 desired passives: 25.0%
Expected eggs: 4 · 90% confidence: about 9 eggs.
Tip: breed parents whose combined pool contains only the passives you want — every extra passive in the pool dilutes your odds. The calculation ignores bonus random passives, which can add junk passives on top but don’t block inheritance.
Empirical side data (Game8, ~100-hatch sample, pre-1.0): passive passed from male parent 24%, female 20%, random-from-both 21%, none 34%; when both parents share a passive it transfers ~46% of the time. These are observational and lower-confidence than the datamined table.
How passive inheritance works
When an egg is produced, the game first rolls how many passives the child inherits from the parents’ combined pool, then picks that many at random from the pool. Extra random passives can be added on top. That means two things: keep the pool clean (only wanted passives on the parents), and expect diminishing odds as you chase more simultaneous passives.
Inheritance probability table
| Passives inherited from parents | Chance |
|---|---|
| 1 | 40% |
| 2 | 30% |
| 3 | 20% |
| 4 | 10% |
First pick the right parent pair with the breeding calculator; if you’re also hunting mutations, check the mutation calculator to budget your cake supply.