Download & Other Tools
- Definition: Ratio of the number of live male births to the number of live female births.
- Data Source: California Dept. of Public Health, Office of Health Information & Research, Vital Statistics Section, Birth Statistical Master Files & Vital Statistics Query System (http://www.apps.cdph.ca.gov/vsq/default.asp); Centers for Disease Control & Prevention, Natality data on CDC WONDER (http://wonder.cdc.gov/) (May 2013).
- Footnote: The county-level data reflect the mother's county of residence, not the county in which the birth occurred. Environmental factors may influence the sex ratio at birth through the effects of chemical pollutants on human sex hormones and their regulation. However, use caution when interpreting year-to-year fluctuations; variation could be the result of environmental effects and/or other factors. LNE (Low Number Event) refers to data that have been suppressed because there were fewer than 20 births. N/A means that data are not available.
- Air Quality
- Child Population
- Public School Enrollment
- Children in Rural and Urban Areas (California & U.S. Only)
- Total Population
- Lead Poisoning
- Sex Ratio at Birth
- Water Quality
- Infant Mortality
- Low Birthweight and Preterm Births
- Why This Topic Is Important
Recent studies have shown that environmental pollutants can affect child health and development (1, 2, 3, 4). For example, exposure to endocrine disruptors (synthetic chemicals found in pesticides and common household items that mimic or block hormones) and second-hand smoke may influence the sex ratio at birth by affecting human sex hormones and their regulation (1, 2, 4, 5). Children are especially vulnerable to toxic substances as their systems are more fragile and their skin is more permeable (4). The expected ratio of males to females born is 1.05 males to every 1 female (1.05:1) (6). Concern mounts when there are fewer males than females born, i.e., less than 1 male to every 1 female (1).
For more information on sex ratio at birth see kidsdata.org’s Research & Links section.
Sources for this narrative:
1. Centers for Disease Control and Prevention. (2010). Sex ratio and the environment. Retrieved from: http://ephtracking.cdc.gov/showRbSrEnv.action
2. Centers for Disease Control and Prevention. (2009). Fourth national report on human exposure to environmental chemicals. Retrieved from: http://www.cdc.gov/exposurereport/
3. California Department of Public Health. (2009). Prematurity & growth retardation. Retrieved from: http://www.ehib.org/page.jsp?page_key=69
4. United States Environmental Protection Agency. (2007). A decade of children's environmental health research: Highlights from EPA's Science to Achieve Results program. Retrieved from: http://www.epa.gov/ncer/publications/research_results_synthesis/
5. The National Institute of Environmental Health Sciences. (2012). Endocrine disruptors. Retrieved from: http://www.niehs.nih.gov/health/topics/agents/endocrine/index.cfm
6. California Department of Public Health. (2010). Sex ratio at birth: Measurement and limitations. Retrieved from: http://www.ehib.org/page.jsp?page_key=117
- How Children Are Faring
In 2011, there were 1.05 male births for every one female birth in California (1.05:1), which is consistent with national figures in previous years. Sex ratios vary across California counties. Use caution when interpreting year-to-year fluctuations; variation could be the result of environmental effects and/or other factors.
Note: Children’s environmental health is an emerging area of research, and the data currently available give a limited picture of how children in California are faring. In many cases, county-level data are not specific enough to inform conclusions about children’s health risks, but they can spark further inquiry.
- Policy Implications
Pound for pound, children are more vulnerable to toxic chemicals in the environment than are adults (1). Toxins that may be present in the air they breathe, in water and beverages they drink, in the food they eat and in the ground on which they play can harm their health.
According to research and experts, policies to improve children’s environmental health, overall, could include:
- Establishing and implementing improved standards and guidelines for school environmental health, addressing areas such as building ventilation, mold prevention, routine cleaning and maintenance, managing chemical exposure, and controlling pests (2)
- Creating healthier school environments by setting appropriate construction standards and fixing structural problems in existing schools (2)
- Focusing broadly on multiple deficiencies and hazards in housing environments and early childhood settings—for example, advancing strategic partnerships among organizations focused on health, education, environmental protection, and housing—instead of focusing on single factors, such as lead or asbestos exposure (3, 4)
- Promoting a research agenda that examines the connections between the built environment and physical and behavioral health, to inform land use policy and regulation of environmental toxins (5)
- Enforcing existing laws and regulations that limit vehicle emissions, agricultural practices that generate dust and pesticide exposure, and industrial practices that generate air pollution (6)
For more policy ideas on environmental health, see the California Adolescent Health Collaborative, the Centers for Disease Control and Prevention’s Healthy Homes Initiative, the California Department of Public Health’s Childhood Lead Poisoning Prevention Branch, and the Center for Children’s Environmental Health. Also see policy implications under the Asthma topic on kidsdata.org.
Sources for this narrative:
1. Landrigan, P. J. & Carlson, J. E. (1995). Environmental policy and children’s health. Future of Children, (5)2, 34-52. Retrieved from: http://futureofchildren.org/futureofchildren/publications/docs/05_02_04.pdf
2. California Air Resources Board and California Department of Health Care Services. (2004). Report to the California legislature: Environmental health conditions in California’s portable classrooms. Retrieved from: http://www.arb.ca.gov/research/apr/reports/l3006.pdf
3. Centers for Disease Control and Prevention. Healthy Homes Initiative. Retrieved from: http://www.cdc.gov/nceh/lead/healthyhomes.htm
4. Bachrach, A., et al. (2010). Environmental health in early childhood systems building: opportunities for states. National Center for Children in Poverty. Retrieved from: http://www.nccp.org/publications/pdf/text_981.pdf
5. Lane, S. D., et al. (2008). Environmental injustice: childhood lead poisoning, teen pregnancy, and tobacco. Journal of Adolescent Health, 42(1), 43-49. Retrieved from: http://www.jahonline.org/article/S1054-139X%2807%2900294-7/abstract
6. Salam, M. T., et al. (2008). Recent evidence for adverse effects of residential proximity to traffic sources on asthma. Current Opinion in Pulmonary Medicine, 14(1), 3-8. Retrieved from: http://sunscreamer.com/publiccomment/Documents/salam%20mt%20traffic%20asthma%20pulm%20opin%202008.pdf
- Websites with Related Information
- America’s Children and the Environment
- California Communities Environmental Health Screening Tool, California Environmental Protection Agency & the Office of Environmental Health Hazard Assessment
- California Environmental Health Tracking Program, California Department of Public Health
- Center for Health and the Global Environment, Harvard Medical School
- Children’s Environmental Health Network
- Environmental Health Perspectives
- Environmental Protection Agency: Children’s Health Protection Program
- Healthy Homes Initiative, Centers for Disease Control and Prevention
- National Environmental Public Health Tracking Network, Centers for Disease Control and Prevention
- National Institute of Environmental Health Sciences, National Institutes of Health
- Key Reports
- A Decade of Children’s Environmental Health Research, Environmental Protection Agency & Children’s Health Protection Program
- America’s Children and the Environment, Third Edition, U.S. Environmental Protection Agency
- Children’s Exposure to Elemental Mercury: National Report of Exposure Events, The Agency for Toxic Substances and Disease Registry & Centers for Disease Control and Prevention
- Environmental Health in Early Childhood Systems Building: Opportunities for States, National Center for Children in Poverty
- Fourth National Report on Human Exposure to Environmental Chemicals, Centers for Disease Control and Prevention
- The Children's Health Study, California Environmental Protection Agency
- The Future of Cancer Research: Accelerating Scientific Innovation Annual Report 2010-2011, U.S. Department of Health and Human Services, National Institutes of Health & National Cancer Institute