Kass isn't Catholic (I'm pretty sure he's Jewish), but he is a very prominent American bioethicist and I haven't yet encountered anything of his I vehemently disagree with -- a rarity with believing Catholics and bioethicists! With those cards on the table, first I'll give you the run-down on his creds, then I'll post the talks. Enjoy:

Leon Kass (born February 12, 1939) is an American bioethicist, best known as a leader in the effort to stop human embryonic stem cell and cloning research as former chair of the President's Council on Bioethics from 2002–2005.

He obtained S.B. and M.D. degrees (1958; 1962) at the University of Chicago and obtained a Ph.D. in biochemistry (1967) at Harvard University. He then taught at St. John's College from 1972 to 1976. He currently retains a position as a member of the President's Council and is the Addie Clark Harding Professor in the College and the Committee on Social Thought at the University of Chicago, and is the author of several books, including Toward A More Natural Science: Biology and Human Affairs; The Hungry Soul: Eating and the Perfecting of our Nature; Life, Liberty, and the Defense of Dignity: The Challenge for Bioethics; and The Beginning of Wisdom: Reading Genesis.

AUDIO:

1. Leon Kass, on how new technologies have changed the assumptions many people have about their children.

2. The Bioethics Debate and the American Character: A Lecture by Eric Cohen, with comments from Leon Kass:

Event audio, part one (MP3 format, 34 megabytes, 75 minutes playing time)
Event audio, part two (MP3 format, 6 megabytes, 13 minutes playing time)

3. Leon Kass on the (Baptist) Albert Mohler Radio Show - Church, Infertility and Christian Ethics

4. February 4, 2003 - Dr. Leon Kass delivers the Second Annual Rabbi Seymour Siegel Lecture in Medical Ethics: Preventing a Brave New World: Why We Should Ban Human Cloning (.rm format)

BONUS AUDIO:

Nigel Cameron on the obstacles and opportunities facing Christians concerned about bioethics.