Harlequin Generations
Understanding the HSSR generation classification system
Updated Breeding Rules — Effective Fall 2026 Breeding Season
The generation matrix and breeding guidelines below reflect rules that take effect with the Fall 2026 breeding season. Key updates include clarified F0 progression, confirmation that F1-BD and F1 are genetically equivalent, and an updated crossbreeding end date. Lambs conceived in the 2035 breeding season and delivered in spring 2036 will be the last generation eligible for Babydoll Southdown outcrossing. After that point, the breed will be closed to all crossbreeding.
The Highest Generation
AP status can be achieved three ways with the following matings: C X C, AP X C, or AP X AP. This is the highest generation in the HSSR registration process and represents the American Purebred Harlequin. The goal is to reach 500 AP Harlequin sheep, at which point the breed will be closed to all outcrossing. Based on current registry projections, this milestone is expected to be reached by 2032.
A Note on F1-BD and F1
F1-BD (Foundation Cross — Babydoll) and F1 (Foundation) are genetically equivalent. Both represent an animal that is approximately 50% Harlequin genetics. The distinction is one of documentation, not blood percentage:
- F1-BD — the Harlequin parent is a documented, registered Harlequin and the other parent is a registered Babydoll Southdown. This is the current standard for all new foundation crosses.
- F1 — a legacy code used for foundation animals registered before 2018, when the BD distinction was not yet in use. These animals carry the same genetic standing as F1-BD.
Because they are genetically equivalent, F1-BD and F1 animals follow the same breeding rules and produce the same offspring generations when paired with any given mate.
F0 Animals and Breed-Up Eligibility
F0 animals are the result of a Babydoll Southdown bred to a non-registered or pre-registry Harlequin. They carry approximately 50% Harlequin genetics but do not yet have fully documented registered parentage on both sides.
Effective Fall 2026, F0 animals may participate in the breed-up program under the following rules:
- F0 × F1-BD, F1, or higher — offspring are registered as F1-BD, entering the standard breed-up ladder from that point forward.
- F0 × F0 or F0 × Babydoll Southdown — offspring are not registerable.
Crossbreeding End Date
The Babydoll Southdown outcrossing program has a defined end date. The last eligible crossbreeding will occur during the 2035 breeding season, with resulting lambs delivered in spring 2036. No new F1-BD registrations will be accepted for lambs born after spring 2036. Breeders who wish to participate in the foundation cross program should plan their breeding programs accordingly.
Generation Calculator
Use the calculator below to find the offspring generation for any pairing, see the fastest path to AP from any starting generation, and explore the full cross-reference matrix. The matrix reflects the updated rules effective Fall 2026.
Generation Calculator
Select the generation of each parent to see the offspring's registration generation.
Fastest Path to AP — Starting with F1-BD in 2026
Assumes optimal mate sourcing each season. Each row = one lamb crop year.
Note: F1-BD and F1 are genetically equivalent (~50% Harlequin). The "-BD" suffix indicates the Harlequin parent is documented registered stock; F1 is a legacy code from before 2018.
| Lamb Year | Your Animal | Best Mate | Offspring |
|---|---|---|---|
| 2026 | F1-BD | A | F2 |
| 2027 | F2 | F2 | FP |
| 2028 | FP | FP | A |
| 2029 | A | A | B |
| 2030 | B | B | C |
| 2031 | C | C | AP |
Full Cross-Reference Matrix
Rows = RAM generation · Columns = EWE generation · Cell = Offspring generation
F1-BD = F1 (genetically equivalent). F0 bred to F1 or higher produces F1-BD offspring. Like-to-like pairings (e.g. F1×F1) do not step up in generation.
| RAM ↓ / EWE → | BBD | F0 | F1-BD | F1 | F2 | FP | A | B | C | AP |
|---|---|---|---|---|---|---|---|---|---|---|
| BBD | — | — | F0 | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD |
| F0 | — | — | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD | F1-BD |
| F1-BD | F0 | — | F1-BD | F1 | F1 | F1 | F2 | F2 | F2 | F2 |
| F1 | F1-BD | — | F1 | F1 | F2 | F2 | F2 | F2 | F2 | F2 |
| F2 | F1-BD | — | F1 | F2 | FP | FP | FP | FP | FP | FP |
| FP | F1-BD | — | F1 | F2 | FP | A | A | A | A | A |
| A | F1-BD | F1-BD | F2 | F2 | FP | A | B | B | B | B |
| B | F1-BD | F1-BD | F2 | F2 | FP | A | B | C | C | C |
| C | F1-BD | F1-BD | F2 | F2 | FP | A | B | C | AP | AP |
| AP | F1-BD | F1-BD | F2 | F2 | FP | A | B | C | AP | AP |
Click any cell to load that pairing into the calculator above. — = Not Registerable.
Generation Summary
| Generation | Category | Parent Requirements |
|---|---|---|
| F0 | Pre-Foundation | Babydoll Southdown × unregistered or pre-registry Harlequin — offspring not registerable unless bred to F1-BD/F1 or higher |
| F1-BD | Foundation Cross | Registered Harlequin × Registered Babydoll Southdown (current standard; genetically equivalent to F1) |
| F1 | Foundation Cross (Legacy) | Legacy code for foundation animals registered before 2018; genetically equivalent to F1-BD |
| F2 | Foundation | F1 or F1-BD × F2, FP, or higher generation |
| FP | Foundation Pure | F2 × F2, or F2 × higher generation |
| A | True Harlequin | FP × FP, or FP × higher generation |
| B | True Harlequin | A × A, or A × higher generation |
| C | True Harlequin | B × B, or B × higher generation |
| AP | American Purebred | C X C, AP X C, or AP X AP |
* Like-to-like pairings (e.g. F1 × F1, FP × FP) do not advance the generation — a mate of at least the next generation is required to step up. See the Generation Calculator above for the full cross-reference matrix.
The Harlequin Generations Program
Based on the need to increase the gene pool, HSSR closed the Open Registration program as of January 1, 2023. In its place, HSSR introduced a definitive program for outcrossing registered Harlequins to registered Babydoll Southdown sheep.
Babydolls were chosen as the only approved outcross for two reasons: first, Southdown rams were used in the original breed development; second, Babydoll Southdowns offer the opportunity to produce shorter sheep. The primary goal is preserving the Harlequin appearance while bringing shoulder height consistently to 24" or shorter (but not less than 19").
These guidelines apply to all lambs born and registered from 2023 through 2035, at which time no further outcrossing will be allowed.
Foundation Harlequins
F1-BD identifies lambs on their Certificate of Registration (CoR) as a 50% registered Harlequin / 50% registered Babydoll Southdown cross.
F2: One parent is F1 and the other parent is a Harlequin of a higher generation, or both parents are F1.
FP (Foundation Pure): One or both parents are F2, or one parent is F2 and the other is a Harlequin of a higher generation.
True Harlequins
A: One or both parents are FP, or one parent is FP and the other is a Harlequin of a higher generation.
B: One or both parents are A, or one parent is A and the other is a Harlequin of a higher generation.
C: One or both parents are B, or one parent is B and the other is a Harlequin of a higher generation.
Purebred Harlequins
AP (American Purebred): Both parents are C Generation. This is the highest generation in the Harlequin registration process and represents the culmination of the breed development program.