Darwin's theories of evolution by natural selection were used to try to show women's place in society was the result of nature. One of the first women to critique Darwin, Antoinette Brown Blackwell published "The Sexes Throughout Nature" in 1875. She was aware she would be considered presumptuous for criticising evolutionary theory but wrote that "disadvantages under which we are placed...will never be lessened by waiting". Blackwell's book answered Darwin and Herbert Spencer, who she thought were the two most influential living men. She wrote of "defrauded womanhood" and her fears that "the human race, forever retarding its own advancement...could not recognize and promote a genuine, broad, and healthful equilibrium of the sexes".