The Declaration of Sentiments was the first ever attempt to formalize equal rights in the United States. The document was signed during the first women's rights convention in Seneca Falls, New York in 1848. The author of the document was Elizabeth Cady Stanton, who used the Declaration of Independence as a mold.
By including the word "women", Stanton made it clear that both Men and Women were equal to the eyes of God and should deserve the same opportunities as Men. This, combined with the highly emotive content of the Declaration of Independence made it possible for 32 men out of the 100 signatories to sign the document.