These words were quoted by the conservative writer Cal Thomas as coming from Professing Feminism, a book by Daphne Patai and Noretta Koertge which he mistakenly ascribed to Catharine MacKinnon.
http://www.snopes.com/quotes/mackinno.htm
The actual passage in that book are the authors' characterization of MacKinnon's views rather than a direct quotation: And Andrea Dworkin and Catharine MacKinnon have long argued that in a patriarchal society all heterosexual intercourse is rape because women, as a group, are not in a strong enough social position to give meaningful consent—an assault on individual female autonomy uncannily reminiscent of old arguments for why women should not have political rights.
Instead MacKinnon argues that heterosexuality "institutionalizes male sexual dominance and female sexual submission" (1982) and that "Sexual access is regularly forced or pressured or routinized beyond denial" (1991).
Misattributed
Catharine A. MacKinnon: Rape
Catharine A. MacKinnon is American feminist and legal activist. Explore interesting quotes on rape.“Politically, I call it rape whenever a woman has sex and feels violated.”
"A Rally Against Rape" (1981), p. 82
Feminism Unmodified: Discourses on Life and Law (1987)
“Compare victims' reports of rape with women's reports of sex. They look a lot alike”
Sexuality, Pornography, and Method: "Pleasure under Patriarchy" (1989) Ethics, Vol. 99, No. 2 pp. 314-346
Source: Feminism, Marxism, Method, and the State: Toward Feminist Jurisprudence (1983) Signs Vol. 8 No. 4, p. 647
“Women are raped and coerced into sex.”
Source: Reflections on Sex Equality under Law (1991) Yale Law Journal Vol.100 No. 5, p. 1213
Sexuality, Pornography, and Method: "Pleasure under Patriarchy" (1989) Ethics, Vol. 99, No. 2 pp. 314-346
"The Prime of Miss Kitty MacKinnon" http://susiebright.blogs.com/Old_Static_Site_Files/Prime_Of_Kitty_MacKinnon.pdf, by Susie Bright, East Bay Express, October 1993.