philosophical anthropology and philosophy of religion, as well as theological ones.
These findings support the claim that the reported amount of extramarital sex differs across cultures and across genders.
Recent surveys conducted in non-Western nations have also found cultural and gender differences in extramarital sex.
Convenience samples do not accurately reflect the population of the United States as a whole, which can cause serious biases in survey results.
It should not be surprising, therefore, that surveys of extramarital sex in the United States have produced widely differing results.
Research by Colleen Hoffon of 566 homosexual male couples from the San Francisco Bay Area found that 45% had monogamous relationships.
That study was funded by the National Institute of Mental Health.
These studies report that about 12–26% of married women and 15–43% of married men engage in extramarital sex.
The only way to get scientifically reliable estimates of extramarital sex is to use nationally representative samples.
The amount of extramarital sex by men is described as "universal" in 6 cultures, "moderate" in 29 cultures, "occasional" in 6 cultures, and "uncommon" in 10 cultures.