Examples

Potter

? + ? = 
1. Henry

Henry + ? =
1. Fleamont
* d.c. 1979

Fleamont + Euphemia? =
1. James
* 1960 - 1981

James + Lily Evans = 
1. Harry (James)
* b. 1980

Harry, Ronald Weasley and Hermione Granger - friends

Harry + Ginny Weasley =
1. James (Sirius)
* b.c. 2004
2. Albus (Severus)
* b.c. 2006
3. Lily (Luna)
* b.c. 2008

Evans

? + ? =
1. Petunia
2. Lily (J)
* 1960 - 1981

Weasley

Septimus + Cedrella Black =
1. son?
2. son?
3. Arthur

Arthur + Molly Prewett =
1. William
2. Charles
3. Percy
4. George
5. Fred
6. Ronald
7. Ginevra (Ginny) Potter
* b. 1981

William + Fleur Delacour =
1. Vistorie
2. Dominique
3. Lousis

Percy + Audrey? =
1. Molly
2. Lucy

George + Angelina Johnson =
1. Fred
2. Roxanne

Ronald + Hermione Granger =
1. Rose
2. Hugo


Granger (Wilkins)

Wendell + Monica? =
1. Hermione