On kidsdata.org, measures of children's family and household structure include: households with children ages 0-17, children living with parents or other relatives overall and by race/ethnicity, children in cohabitating couple households, children in same-sex couple households, and children in the care of grandparents. Depending on the indicator, data come from the American Community Survey or Current Population Survey and are available for:

• California and the U.S., as single-year estimates
• Cities, school districts, and counties with 65,000 residents or more, as single-year estimates
• Cities, school districts, and counties with 10,000 residents or more, as 5-year estimates
• Legislative districts, as 5-year estimates

In addition, kidsdata.org's measures of youth housing situation present characteristics of where and with whom students in grades 7, 9, 11, and non-traditional programs live. These estimates come from the California Healthy Kids Survey and are based on youth self-reports by grade level, gender, level of school connectedness,* parent education level, race/ethnicity, and sexual orientation.

Child well being is strongly influenced by the family environment and the presence of caring, stable adults (1). While children can thrive in any kind of family structure (e.g., in the care of grandparents, single-parents, same-sex parents, etc.), the stability of the family and the nature of family relationships are important factors in child development (1, 2, 3). Research shows that unstable home environments can adversely affect children's health and well being (2, 3, 4). Financial stability is important, too, and is linked to family structure (3, 5, 6). For example, single and cohabiting parents are more likely than married parents to have lower incomes and experience financial difficulty (3, 5). Financial hardship can cause family stress and hinder the ability to provide the environment and experiences a child needs for optimal cognitive, emotional, and physical development (3, 6).

Kidsdata.org's family structure topic also includes data on youth housing situation, which can provide insight into stability and vulnerability in young people's lives. For example, youth living in multi-family (overcrowded) homes, in hotels/motels, or with friends may be homeless or at risk of homelessness. Poverty and housing insecurity put young people at risk of poor health and developmental outcomes throughout their life course (4, 6). Additionally, youth living in foster care or group homes are a particularly vulnerable population, facing increased risks of emotional, physical, behavioral, and academic problems (7).

In 2017, the estimated share of California households with one or more children ages 0-17 was 34%, down from 38% a decade earlier. Statewide, 64% of California children lived with two parents in 2017, 23% lived with their mother only, 8% with their father only, and 4% with non-parent relatives. Additionally, 9% of children lived in households with unmarried couples and 3% lived in the care of their grandparents. Across counties with data in 2013-2017, family structure varied widely, from 51% to 76% of children living in two-parent households, 0.3% to 16% living in cohabitating couple households, and 0.1% to 7% in the care of grandparents. In 2016, 0.1% of California children lived in households with married or unmarried same-sex couples, compared with 0.2% nationally.

According to a survey of California youth, around 9 out of every 10 students in Grades 7, 9, and 11 lived in a home with one or more parents or guardians in 2015-2017. During the same period, fewer than 1 in 20 lived in a home with more than one family, and fewer than 1 in 40 lived in the home of another relative. Statewide, students in non-traditional programs, those with low levels of school connectedness, and those whose parents did not finish high school are less likely to live in a parent's or guardian's home than their peers in other groups.

Families and caregivers provide an essential safety net for children. Public policy can help support and reinforce that safety net for the good of the family and for society at large. While children can thrive in any type of family structure, the stability of the family is critical for positive child development (1, 2). Stable home environments also are important, as children and youth without safe, secure housing are at risk for poor health outcomes (1, 3).

Family types have become increasingly diverse in recent decades, and research indicates that some families may need more support than others (4). Single- and cohabiting-parent families, for example, are more likely to live in poverty than married-parent families (4). In addition, non-parental caregivers, such as grandparents, may need information, financial and emotional support, and authority to provide for children in their care (5, 6). Further, families headed by same-sex parents may face challenges with social stigma and discrimination (7, 8).

Policy options that could support vulnerable families and increase their stability include:

• Strengthening the social and financial safety net for low-income families and working parents so that they can reduce stress and promote stable environments for their children, e.g., through adequate cash assistance, child care subsidies, and evidence-based efforts (such as home-visiting programs) that provide parents/caregivers with information and support as needed (1, 2, 9)
• Promoting responsible fatherhood programs, especially for nonresidential fathers, that are comprehensive and address child support collection issues, paternal employment and education, and parenting skills (10)
• Supporting policies to reduce unintended pregnancies (e.g., through use of long-acting reversible contraception), as these are more likely to occur in and lead to unstable families (2)
• Ensuring that policies and programs are in place to boost educational attainment, particularly for young women, as education is a key predictor of family stability (2)
• Continuing to advance policies and strategies to ensure that relatives caring for children (e.g., grandparents) have the full range of support needed to provide for them, meet their education and health needs, and avoid placement in non-relative foster care (5, 6)
• Supporting policies and strategies aimed at reducing social stigma and discrimination against LGBTQ populations, as anti-gay policies and attitudes can negatively affect same-sex parents, their children, and LGBTQ youth (7, 8)
• Promoting policies and programs to ensure stable housing for vulnerable youth, including youth in foster care or the juvenile justice system, LGBTQ youth, and those who are disconnected from school and work (11)
• Promoting residential stability through cross-sector and local/state collaboration to increase the supply of affordable housing, address restrictive zoning and planning regulations, make housing more affordable to low-income families (e.g., through rental assistance), and provide permanent housing for families at risk of homelessness (12)