We often hear that using two condoms increases the risk of breakage, but exactly how has that been determined?
I spent considerable time on the Internet trying to find actual research that shows that using two condoms increases the risk of breakage and found NOTHING to support that belief. There are many incorrect ideas which have been repeated over and over 'til they become widely accepted. For example, until recently, it was widely believed that Marie Antoinette said, "Let them eat cake." Now many historians doubt that she actually said it; it looks as though one historian misquoted her and the misquote was copied over and over by other historians 'til it was widely believed. And we know that for centuries doctors bled people thinking that it would improve their health. Thus, the risks of accepting unsupported ideas should be clear.
A study in Thailand indicated lower breakage rate when two condoms were used:
Multiple Condom Use and Decreased Condom Breakage and Slippa... : JAIDS Journal of Acquired Immune Deficiency Syndromes
A study in a Nevada brothel indicated that some women used two condoms, but nothing is said about the resulting breakage rate:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1615688/pdf/amjph00449-0044.pdf
I'm hoping that others will do some research work, but reject any ideas which are not backed up with actual research.
Probably I should have started a new thread for this post, but I was unable to figure out how to do it.