Evidence of socio-economic stress and female foeticide in racial disparities in the gender ratio at birth in the United States (1995-2014).

BACKGROUND: Males are born in excess of females, expressed as M/T (male/total births), which is expected to approximate 0.515. Racial M/T disparities have been long known. This study was carried out in order to identify such disparities in different races in the United States.
DESIGN: Monthly male and female live births by race for the entire US were obtained from the website of the Centers for Disease Control and Prevention for 1995-2014 for the four racial groups: American Indian or Alaska Native, Asian or Pacific Islander, Black or African American and White.
RESULTS: This study analysed 80805992 live births (M/T 0.5117). M/T was Asian or Pacific Islander>White>American Indian or Alaska Native>Black or African American. The M/T gradient across races was highly significant (p<0.0001).
CONCLUSIONS: The perinatal mortality rate is an important indicator of quality of health care delivery and is expected to approximate 6/1000 births. M/T declines in association with surrogates of socioeconomic status, presumably due to higher stress levels. The lower baseline M/T of Indian or Alaska Native and Black and African American is equivalent to a constant reduction of 3.5-4/1000 male births when compared to White M/T. Race is the most significant variable associated with wealth inequality in the US and may be partially responsible. Sex-selective abortion and the application of a male offspring preference stopping rule is widespread in Asia its immigrants, and in this study is equivalent a constant loss of 3.5 females foetuses per 1000 live births when compared to Whites.