Are Endocrine Disruptors Changing Birth Ratios?
Author Information
Author(s): Barrett Julia R.
Hypothesis
Paternal exposures to endocrine-disrupting chemicals might affect the expression of the SRY gene on the Y chromosome.
Conclusion
The study reveals significant male-to-female shifts in birth ratios in Japan and the United States, potentially linked to endocrine disruptors.
Supporting Evidence
- An average of 105 boys are born for every 100 girls.
- The male proportion of births in Japan declined from 0.5172 to 0.5135 from 1949 to 1999.
- The male fetal death rate is approximately four times higher in Japan than in the United States.
- In the U.S., the proportion of male births dropped from 0.5134 in 1970 to 0.5117 in 2002.
- The proportion of non-Hispanic white male births fell from 0.5143 to 0.5122 between 1970 and 2002.
Takeaway
This study looks at how many boys and girls are born and suggests that chemicals in the environment might be affecting these numbers.
Methodology
The study analyzed birth and fetal death sex ratios using demographic data from Japan and the United States over several decades.
Limitations
The reasons for differences in birth ratios between racial groups remain unclear.
Participant Demographics
The study included demographic data from Japan and the United States, focusing on racial differences in birth ratios.
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