Kidsdata.org offers data on the ratio of live male births to live female births.
Note: The information presented for this topic is not exhaustive of all relevant data, and has limitations. Kidsdata offers these and other data to draw attention to the
environmental influences on children's health and to encourage
exploration of the
issues. These indicators will be revised as new data emerge from
initiatives such as the National Children's Study and are updated in the California Environmental Health Tracking Program site.
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:
- Centers for Disease Control and Prevention. (2010). Sex ratio and the environment. Retrieved from: http://ephtracking.cdc.gov/showRbSrEnv.action
- Centers for Disease Control and Prevention. (2009). Fourth national report on human exposure to environmental chemicals. Retrieved from: http://www.cdc.gov/exposurereport/
- California Department of Public Health. (2009). Prematurity & growth retardation. Retrieved from: http://www.ehib.org/page.jsp?page_key=69
- 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/
- The National Institute of Environmental Health Sciences. (2012). Endocrine disruptors. Retrieved from: http://www.niehs.nih.gov/health/topics/agents/endocrine/index.cfm
- California Department of Public Health. (2010). Sex ratio at birth: Measurement and limitations. Retrieved from: http://www.ehib.org/page.jsp?page_key=117
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
- 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
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:
- 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
- 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
- Centers for Disease Control and Prevention. Healthy Homes Initiative. Retrieved from: http://www.cdc.gov/nceh/lead/healthyhomes.htm
- 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
- 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
- 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
In 2010, 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 and over time. 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.