Does Thomas Aquinas say that woman is misbegotten? No.
On the contrary, Aquinas denies it no fewer than six times:
3. Summa Theologiae, 1, 92, 1, ad 1.
4. Summa Theologiae, 1, 99, 2, ad 1.
6. Summa Contra Gentiles, 3, 94, n. 10.
For more information:
Michael Nolan, "What Aquinas Never Said About Women," First Things 87 (November 1998) 11-12.
Michael Nolan, "The Aristotelian Background to Aquinas's Denial that 'Woman is a Defective Male'," The Thomist 64 (2000): 21-69. [PDF]
Michael Nolan, Aquinas' Philosophy of Man and Woman (Dublin: Four Courts Press, 1998).
Michael Nolan, Defective Tales: The Story of Three Myths (Ireland, Printcomp Ltd., 1995).
See also:
Michael Nolan, "The Defective Male: What Aquinas Really Said,"New Blackfriars 75.880 (March 1994): 156-166.
Michael Nolan, "Passive and Deformed? Did Aristotle Really Say This?", New Blackfriars 76.893 (May 1995): 237-257.
Michael Nolan, "Aquinas and the Act of Love," New Blackfriars 77.902 (March 1996): 115-130.
Michael Nolan, "Aquinas and the Act of Love," in At the Heart of the Real: Philosophical essays in honour of the Most Reverend Desmond Connell, Archbishop of Dublin (Dublin: Irish Academic Press, 1992), 163-76.
Robert Mayhew, The Female in Aristotle's Biology (Chicago: University of Chicago Press, 2004).