More Boys Born Than Girls

New Report Documents Total Gender Ratios At Birth From 1940 to 2002

For Release: June 14, 2005

Contact: CDC National Center for Health Statistics Press Office (301) 458-4800

E-mail: paoquery@cdc.gov

Trend Analysis of the Sex Ratio at Birth in the United States. NVSR Volume 53, Number 20. 18 pp. (PHS) 2004-1120 pdf icon[PDF – 1.4 MB]

For the 63d year in a row, the number of boys born in the United States outnumbers births of girls -– in 2002, 94,232 more boys than girls were born. This is the central finding of a new Centers for Disease Control and Prevention (CDC) report that examines total sex ratios at birth for over six decades. The total sex ratio is the number of male births divided by female births times 1,000. Other findings of the report are:

• Since 1940, an average of 91,685 more male babies have been born each year than females, a total of 5,776,130 over that 63-year period.
• The highest sex birth ratio occurred in 1946 (1,059 male births per 1,000 females) while the lowest occurred in 1991 and again in 2001 (1,046 male births per 1,000 females).
• There were three major trends in sex birth ratios over this period: a significant decline between 1942 and 1959; a significant increase between 1959 and 1971; and another significant decline between 1971 and 2002.
• Combining all the years studied, older mothers (40 to 44 years of age and 45 years and over) have the lowest total sex birth ratios (1,038 and 1,039, respectively) and mothers 15 to 19 years of age had the highest sex birth ratio (1,054).
• The more children a woman has the more likely she is going to give birth to an equal number of boys and girls.
• For all available years combined, Chinese mothers (1,074) and Filipino mothers (1,072) had the highest differences between the number of boys born compared with girls, whereas non-Hispanic black mothers (1,031) and American Indian mothers (1,031) had the lowest.

The report, “Trend Analysis of the Sex Ratio at Birth in the United States,” was prepared by CDC’s National Center for Health Statistics (NCHS) and is available at the CDC/NCHS Web site.