Your question is a somewhat difficult one, as the "why" of something is not something answerable as a reference question, unless we can find sources discussing the "why." In any event, here is some information that will hopefully help you with the background for your article.
First, the following statistical sheets may change your perception of abortion attitudes among women today:
"Abortion: People's Chief Concerns" - Men and women hold similar views on the legality of abortion (Public Agenda) and "Abortion: People's Chief Concerns" - Views on abortion have not changed significantly since the 1970s (Public Agenda).
"Young People Have Mixed Views On Abortion; But Strong Support For Sex Education And Gay Rights" (Kaiser Family Foundation) is another relevant opinion poll. And here is one about religion in public life: "For Goodness' Sake: Why So Many Want Religion to Play a Greater Roll in American Life" (Public Agenda).
The recent collection The Cost of "Choice": Women Evaluate the Impact of Abortion, edited by Erika Bachiochi, may shed some light on your question. Other recent books are Abortion Politics in North America by Melissa Haussman and Bearing Right: How Conservatives Won the Abortion War by William Saletan.
Following are some articles you may find helpful. Most are available through some EBSCO databases that your local public library probably has access to:
"Attitudes toward Abortion, Religion, and Party Affiliation among College Students" by Jennifer A. Hess and Justin D. Rueb. Current Psychology; Spring2005, Vol. 24 Issue 1, p24-42.
"The Structure and Effects of Moral Predispositions in Contemporary American Politics by Herbert F. Weisberg. Journal of Politics; Aug2005, Vol. 67 Issue 3, p646-668.
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"Is the Personal Always Political? A Cross-Cultural Analysis of Abortion Attitudes" by Gail Sahar and Kaori Karasawa. Basic & Applied Social Psychology; Dec2005, Vol. 27 Issue 4, p285-296.
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"Which 'Roe Effect'?" by Elizabeth Fox-Genovese. Society; Jul/Aug2005, Vol. 42 Issue 5.
"Trends in Abortion Attitude among Young Adults: 1977-1993" by Ranjita Misra and Steven Hohman. American Journal of Health Studies; 2000, Vol. 16 Issue 2, p85.
"The Measurement of Public Opinion on Abortion: The Effects of Survey Design" by Larry L. Bumpass. Family Planning Perspectives; Jul/Aug97, Vol. 29 Issue 4, p177-180.
"Unwanted births increase among American women: An attitude shift or fewer abortion providers are seen as possible reasons" by Mike Stobbe. Houston Chronicle. Dec 20, 2005. pg. 10
"Berkeley study finds youth more conservative than parents." Black Issues in Higher Education, Oct 24, 2002.Vol.19, Iss. 18; pg. 20
In terms of finding experts to interview, you may want to contact people at the organizations listed on Public Agenda's Sources and Resources page, or the experts on this conference resource list (in PDF), even though it is three years old.
