What do own children mean?

When I tried to create child care variables, I saw household/non-household own/non-own children. What do own children mean? Are stepchildren and children of cohabiting parnter from previous relationships non-own children or own children??

non-own household children: such as siblings or grandchildren;

non-own nonhousehold children, such as a neighbor‘s children.

Household children. Household children are children under age 18 residing in the household of the ATUS respondent. The children may be related to the respondent (such as their own children, grandchildren, nieces or nephews, or brothers or sisters) or not related (such as foster children or children of roommates or boarders). For secondary childcare calculations, respondents are asked about care for household children under age 13.

Own children. This refers to the respondent‘s own children, whether they live in the respondent‘s household or in another household. Stepchildren and adopted children are considered own children, although foster children are not. For secondary childcare calculations, respondents are asked about care for own children under age 13—those living in the respondent‘s household and those living in other households.