• They establish that very low levels of bisphenol A, the basic building block of polycarbonate plastic, when fed to female mice during pregnancy cause the prostate of male offspring to become signficantly larger than normal and hypersensitized to subsequent hormonal stimulation.
  
  
• They determine that the amount of bisphenol A required to cause this is comparable, relative to body weight, of ongoing human exposure to bisphenol A:

    "Xenoestrogens are often referred to as weak estrogens that are not likely to be biologically active at environmentally relevant concentrations. In our study, a maternal dose of only 2 µg/kg/day bisphenol A enlarged the prostate in male offspring. This dose is equivalent to a daily dose of 50 µgs for a 25-kg child or 150 µgs for a 75-kg adult. In this regard, Olea et al. have shown that after a 50-mg dental sealant treatment, the saliva measured in a 1-hr collection after the application of the sealant from human subjects contained from 90 to 931 µg of bisphenol A. They also measured bisphenol A in the saliva of an individual who had tooth sealant applied 2 years earlier and found 66.4 µgs in a 1-hr saliva collection before additional sealnt treatment, suggesting that bisphenol A may be continually released after the initial dental work. Brotons et al. analyzed vegetables packaged in food cans with lacquer coating and found that as much as 23 µgs of bisphenol A was recovered from 50 ml of the liquid portion of one food can."
  

• They report that serum binding proteins are more effective at reducing the biological activity of estradiol and octylphenol than of bisphenol A. "The activity of bisphenol A was slightly enhanced in serum while the activity of nonylphenol and octylphenol was dramatically decreased relative to estradiol."

Olea, N, R Pulgar, P Perez, F Olea-Serrano, A Rivas, A Novillo-Fertrell, V Pedraza, A Soto and C Sonnenschein. 1996. Estrogenicity of resin-based composites and sealants used in dentistry. Environmental Health Perspectives 104(3):298-305.

The amazing discovery in this paper is that bisphenol-F is estrogenic. What is astonishing about this is that bisphenol-F is produced by a process patented in 1909 by LH Baekeland, involving the reaction between phenol and formaldehyde. It was this process that Baekeland discovered could be used to produce what he called bakelite...or bisphenol F. Bakelite became the first "miracle plastic" to move into global commerce, used in an enormous variety of consumer products. Many people can recall, for example, the smell of burning bakelite used to make components of kitchen ovens. The implication is that people have been exposed to synthetic estrogenic substances since early in the 20th century.

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