Readers who are interested in Prof. Stassen's most recent articulations on abortion ethics should consult his book, Kingdom Ethics: Following Jesus in Contemporary Context (Downers Grove, Ill.: InterVarsity Press, 2003), co-authored with David Gushee.
In personal correspondence, Prof. Stassen tells me that he did not remember the 1977 statement "A Call to Concern" being in support of Roe v. Wade, and that positions do indeed change over the years. Fair enough. As I said above, those interested in knowing his current position should consult his book.
I want to thank Prof. Stassen for his prompt and cordial interaction. We certainly disagree on a number of significant issues, but I believe the dialogue can be important.