| Value | Category |
|---|---|
| 0 | Mother and father deceased |
| 1 | Mother and father don't know |
| 2 | Mother deceased, father don't know |
| 3 | Mother deceased, father alive |
| 4 | Mother don't know, father deceased |
| 5 | Mother don't know, father alive |
| 6 | Mother alive, father deceased |
| 7 | Mother alive, father don't know |
| 8 | Mother and father allive |
| Sysmiss |