backend/app/api/v1/cleanup.py

@@ -6,6 +6,7 @@ from app.api.deps import CurrentUser, SessionDep
 from app.schemas.cleanup import (
     CleanupResult,
     DeceasedApply,
+    DeceasedByChildCandidate,
     DeceasedCandidate,
     GenderApply,
     GenderProposal,
@@ -31,6 +32,24 @@ async def preview_deceased(
     return [DeceasedCandidate(**r) for r in rows]
 
 
+@router.get(
+    "/{tree_id}/cleanup/deceased-by-child", response_model=list[DeceasedByChildCandidate]
+)
+async def preview_deceased_by_child(
+    tree_id: uuid.UUID,
+    session: SessionDep,
+    current: CurrentUser,
+    born_on_or_before: int = 1900,
+) -> list[DeceasedByChildCandidate]:
+    """People with a child born on/before the cutoff — necessarily deceased even
+    when their own birth date is missing. Apply via POST .../cleanup/deceased."""
+    tree = await tree_service.get_tree(session, viewer_id=current.id, tree_id=tree_id)
+    rows = await cleanup_service.preview_deceased_by_child(
+        session, actor=current, tree=tree, year=born_on_or_before
+    )
+    return [DeceasedByChildCandidate(**r) for r in rows]
+
+
 @router.post("/{tree_id}/cleanup/deceased", response_model=CleanupResult)
 async def apply_deceased(
     tree_id: uuid.UUID, data: DeceasedApply, session: SessionDep, current: CurrentUser

backend/app/schemas/cleanup.py

@@ -9,6 +9,12 @@ class DeceasedCandidate(BaseModel):
     birth_year: int
 
 
+class DeceasedByChildCandidate(BaseModel):
+    person_id: uuid.UUID
+    name: str
+    child_birth_year: int
+
+
 class DeceasedApply(BaseModel):
     person_ids: list[uuid.UUID]
 

backend/app/services/cleanup_service.py

@@ -133,6 +133,51 @@ async def apply_deceased(
     return len(persons)
 
 
+# ---- 1b. Mark deceased by a CHILD's birth year -------------------------------------
+# For parents whose own birth date is missing (so the birth-year rule can't reach
+# them) but who have a child born long ago — they're necessarily deceased. Applies
+# through the same apply_deceased() path.
+
+async def preview_deceased_by_child(
+    session: AsyncSession, *, actor: User, tree: Tree, year: int
+) -> list[dict]:
+    await _require_editor(session, actor=actor, tree=tree)
+    names = await _primary_name_by_person(session, tree.id)
+    years = await _birth_year_by_person(session, tree.id)
+    rels = (
+        await session.execute(
+            select(Relationship).where(
+                Relationship.tree_id == tree.id,
+                Relationship.deleted_at.is_(None),
+                Relationship.type == RelationshipType.parent_child,
+            )
+        )
+    ).scalars().all()
+    # parent id -> earliest child birth year, among children born on/before `year`.
+    earliest_child: dict[uuid.UUID, int] = {}
+    for r in rels:
+        cy = years.get(r.person_to_id)  # the child's birth year
+        if cy is None or cy > year:
+            continue
+        if r.person_from_id not in earliest_child or cy < earliest_child[r.person_from_id]:
+            earliest_child[r.person_from_id] = cy
+    persons = {p.id: p for p in await _persons(session, tree.id)}
+    out: list[dict] = []
+    for parent_id, cy in earliest_child.items():
+        p = persons.get(parent_id)
+        if p is None or p.is_living is False:  # gone or already deceased
+            continue
+        out.append(
+            {
+                "person_id": str(parent_id),
+                "name": _display(names.get(parent_id)),
+                "child_birth_year": cy,
+            }
+        )
+    out.sort(key=lambda r: r["child_birth_year"])
+    return out
+
+
 # ---- 2. Re-derive gender from a source GEDCOM (matches by name) ----------------------
 
 async def preview_gender(

backend/tests/test_cleanup.py

@@ -51,6 +51,53 @@ async def test_deceased_preview_and_apply(client):
     assert old not in [r["person_id"] for r in prev2]
 
 
+async def test_deceased_by_child_preview_and_apply(client):
+    h, tid = await _tree(client, "cl-decchild@example.com")
+    # Parent with NO birth date (the gap the birth-year rule can't reach).
+    parent = await _person(client, h, tid, "Gesche", "Frerking")
+    child = await _person(client, h, tid, "Kindt", "Frerking")
+    await _birth(client, h, tid, child, 1880)  # child born before the cutoff
+    await client.post(
+        f"/api/v1/trees/{tid}/relationships",
+        json={"type": "parent_child", "person_from_id": parent, "person_to_id": child},
+        headers=h,
+    )
+    # A parent of a modern child must NOT be flagged.
+    p_modern = await _person(client, h, tid, "Modern", "Parent")
+    c_modern = await _person(client, h, tid, "Kid", "Parent")
+    await _birth(client, h, tid, c_modern, 1990)
+    await client.post(
+        f"/api/v1/trees/{tid}/relationships",
+        json={"type": "parent_child", "person_from_id": p_modern, "person_to_id": c_modern},
+        headers=h,
+    )
+
+    prev = (
+        await client.get(
+            f"/api/v1/trees/{tid}/cleanup/deceased-by-child?born_on_or_before=1900", headers=h
+        )
+    ).json()
+    ids = [r["person_id"] for r in prev]
+    assert parent in ids and p_modern not in ids
+    assert next(r for r in prev if r["person_id"] == parent)["child_birth_year"] == 1880
+
+    # Apply through the shared deceased endpoint.
+    r = await client.post(
+        f"/api/v1/trees/{tid}/cleanup/deceased", json={"person_ids": [parent]}, headers=h
+    )
+    assert r.status_code == 200 and r.json()["updated"] == 1
+    assert (
+        await client.get(f"/api/v1/trees/{tid}/persons/{parent}", headers=h)
+    ).json()["is_living"] is False
+    # Re-preview drops the now-deceased parent.
+    prev2 = (
+        await client.get(
+            f"/api/v1/trees/{tid}/cleanup/deceased-by-child?born_on_or_before=1900", headers=h
+        )
+    ).json()
+    assert parent not in [r["person_id"] for r in prev2]
+
+
 async def test_gender_from_spouse_preview_and_apply(client):
     h, tid = await _tree(client, "cl-spouse@example.com")
     husband = (

frontend/app/trees/[id]/cleanup/page.tsx

@@ -10,6 +10,7 @@ import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card";
 import { Input } from "@/components/ui/input";
 
 type Deceased = components["schemas"]["DeceasedCandidate"];
+type DeceasedByChild = components["schemas"]["DeceasedByChildCandidate"];
 type GenderProp = components["schemas"]["GenderProposal"];
 type NameIssue = components["schemas"]["NameIssue"];
 type Person = components["schemas"]["PersonRead"];
@@ -31,6 +32,12 @@ export default function CleanupPage() {
   const [decSel, setDecSel] = useState<Set<string>>(new Set());
   const [decMsg, setDecMsg] = useState<string | null>(null);
 
+  // 1b) Deceased by a child's birth year (for parents with no birth date)
+  const [childYear, setChildYear] = useState(1900);
+  const [decByChild, setDecByChild] = useState<DeceasedByChild[] | null>(null);
+  const [dbcSel, setDbcSel] = useState<Set<string>>(new Set());
+  const [dbcMsg, setDbcMsg] = useState<string | null>(null);
+
   // 2) Gender from source GEDCOM
   const [gender, setGender] = useState<GenderProp[] | null>(null);
   const [genSel, setGenSel] = useState<Set<string>>(new Set());
@@ -63,6 +70,23 @@ export default function CleanupPage() {
     setDeceased(null);
   }
 
+  async function previewDeceasedByChild() {
+    setDbcMsg(null);
+    const { data } = await api.GET("/api/v1/trees/{tree_id}/cleanup/deceased-by-child", {
+      params: { path: { tree_id: treeId }, query: { born_on_or_before: childYear } },
+    });
+    setDecByChild(data ?? []);
+    setDbcSel(new Set((data ?? []).map((d) => d.person_id)));
+  }
+  async function applyDeceasedByChild() {
+    const { data } = await api.POST("/api/v1/trees/{tree_id}/cleanup/deceased", {
+      params: { path: { tree_id: treeId } },
+      body: { person_ids: [...dbcSel] },
+    });
+    setDbcMsg(`Marked ${data?.updated ?? 0} people deceased.`);
+    setDecByChild(null);
+  }
+
   async function previewGender(e: React.ChangeEvent<HTMLInputElement>) {
     const file = e.target.files?.[0];
     if (genFile.current) genFile.current.value = "";
@@ -231,6 +255,59 @@ export default function CleanupPage() {
         </CardContent>
       </Card>
 
+      {/* 1b) Deceased by a child's birth year */}
+      <Card>
+        <CardHeader>
+          <CardTitle className="text-base">Mark deceased by a child’s birth year</CardTitle>
+        </CardHeader>
+        <CardContent className="space-y-3">
+          <p className="text-sm text-[var(--muted)]">
+            Catches parents who have <strong>no birth date of their own</strong> (so the rule
+            above can’t reach them) but who have a child born long ago — they’re necessarily
+            deceased.
+          </p>
+          <div className="flex flex-wrap items-end gap-2">
+            <label className="flex flex-col gap-1 text-sm">
+              <span className="text-xs text-[var(--muted)]">Has a child born on or before</span>
+              <Input
+                type="number"
+                className="w-28"
+                value={childYear}
+                onChange={(e) => setChildYear(Number(e.target.value))}
+              />
+            </label>
+            <Button variant="outline" onClick={previewDeceasedByChild}>
+              Preview
+            </Button>
+          </div>
+          {dbcMsg && <p className="text-sm text-bronze">{dbcMsg}</p>}
+          {decByChild && (
+            <div className="space-y-2">
+              <p className="text-sm text-[var(--muted)]">
+                {decByChild.length} people with a child born ≤ {childYear} (not already marked
+                deceased).
+              </p>
+              <ul className="max-h-64 divide-y divide-[var(--border)] overflow-auto rounded-lg border border-[var(--border)]">
+                {decByChild.map((d) => (
+                  <li key={d.person_id} className="flex items-center gap-3 px-3 py-1.5 text-sm">
+                    <input
+                      type="checkbox"
+                      checked={dbcSel.has(d.person_id)}
+                      onChange={() => toggle(dbcSel, d.person_id, setDbcSel)}
+                    />
+                    <span className="flex-1">{d.name}</span>
+                    <span className="text-xs text-[var(--muted)]">child b. {d.child_birth_year}</span>
+                  </li>
+                ))}
+              </ul>
+              {decByChild.length > 0 && (
+                <Button onClick={applyDeceasedByChild}>Mark {dbcSel.size} deceased</Button>
+              )}
+            </div>
+          )}
+        </CardContent>
+      </Card>
+
       {/* 2) Gender from source */}
       <Card>
         <CardHeader>

frontend/lib/api/schema.d.ts

@@ -718,6 +718,27 @@ export interface paths {
         patch?: never;
         trace?: never;
     };
+    "/api/v1/trees/{tree_id}/cleanup/deceased-by-child": {
+        parameters: {
+            query?: never;
+            header?: never;
+            path?: never;
+            cookie?: never;
+        };
+        /**
+         * Preview Deceased By Child
+         * @description People with a child born on/before the cutoff — necessarily deceased even
+         *     when their own birth date is missing. Apply via POST .../cleanup/deceased.
+         */
+        get: operations["preview_deceased_by_child_api_v1_trees__tree_id__cleanup_deceased_by_child_get"];
+        put?: never;
+        post?: never;
+        delete?: never;
+        options?: never;
+        head?: never;
+        patch?: never;
+        trace?: never;
+    };
     "/api/v1/trees/{tree_id}/cleanup/gender/preview": {
         parameters: {
             query?: never;
@@ -1286,6 +1307,18 @@ export interface components {
             /** Person Ids */
             person_ids: string[];
         };
+        /** DeceasedByChildCandidate */
+        DeceasedByChildCandidate: {
+            /**
+             * Person Id
+             * Format: uuid
+             */
+            person_id: string;
+            /** Name */
+            name: string;
+            /** Child Birth Year */
+            child_birth_year: number;
+        };
         /** DeceasedCandidate */
         DeceasedCandidate: {
             /**
@@ -4013,6 +4046,39 @@ export interface operations {
             };
         };
     };
+    preview_deceased_by_child_api_v1_trees__tree_id__cleanup_deceased_by_child_get: {
+        parameters: {
+            query?: {
+                born_on_or_before?: number;
+            };
+            header?: never;
+            path: {
+                tree_id: string;
+            };
+            cookie?: never;
+        };
+        requestBody?: never;
+        responses: {
+            /** @description Successful Response */
+            200: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["DeceasedByChildCandidate"][];
+                };
+            };
+            /** @description Validation Error */
+            422: {
+                headers: {
+                    [name: string]: unknown;
+                };
+                content: {
+                    "application/json": components["schemas"]["HTTPValidationError"];
+                };
+            };
+        };
+    };
     preview_gender_api_v1_trees__tree_id__cleanup_gender_preview_post: {
         parameters: {
             query?: never;

frontend/openapi.json

@@ -2873,6 +2873,64 @@
         }
       }
     },
+    "/api/v1/trees/{tree_id}/cleanup/deceased-by-child": {
+      "get": {
+        "tags": [
+          "cleanup"
+        ],
+        "summary": "Preview Deceased By Child",
+        "description": "People with a child born on/before the cutoff \u2014 necessarily deceased even\nwhen their own birth date is missing. Apply via POST .../cleanup/deceased.",
+        "operationId": "preview_deceased_by_child_api_v1_trees__tree_id__cleanup_deceased_by_child_get",
+        "parameters": [
+          {
+            "name": "tree_id",
+            "in": "path",
+            "required": true,
+            "schema": {
+              "type": "string",
+              "format": "uuid",
+              "title": "Tree Id"
+            }
+          },
+          {
+            "name": "born_on_or_before",
+            "in": "query",
+            "required": false,
+            "schema": {
+              "type": "integer",
+              "default": 1900,
+              "title": "Born On Or Before"
+            }
+          }
+        ],
+        "responses": {
+          "200": {
+            "description": "Successful Response",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "array",
+                  "items": {
+                    "$ref": "#/components/schemas/DeceasedByChildCandidate"
+                  },
+                  "title": "Response Preview Deceased By Child Api V1 Trees  Tree Id  Cleanup Deceased By Child Get"
+                }
+              }
+            }
+          },
+          "422": {
+            "description": "Validation Error",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "$ref": "#/components/schemas/HTTPValidationError"
+                }
+              }
+            }
+          }
+        }
+      }
+    },
     "/api/v1/trees/{tree_id}/cleanup/gender/preview": {
       "post": {
         "tags": [
@@ -4897,6 +4955,30 @@
         ],
         "title": "DeceasedApply"
       },
+      "DeceasedByChildCandidate": {
+        "properties": {
+          "person_id": {
+            "type": "string",
+            "format": "uuid",
+            "title": "Person Id"
+          },
+          "name": {
+            "type": "string",
+            "title": "Name"
+          },
+          "child_birth_year": {
+            "type": "integer",
+            "title": "Child Birth Year"
+          }
+        },
+        "type": "object",
+        "required": [
+          "person_id",
+          "name",
+          "child_birth_year"
+        ],
+        "title": "DeceasedByChildCandidate"
+      },
       "DeceasedCandidate": {
         "properties": {
           "person_id": {