I am sure it is a cultural difference - but not wrt abortion but marriage.
"In 2011 , 72 percent of all births to black women, 66 percent to American Indian or Alaskan native women, and 53 percent to Hispanic women occurred outside of marriage, compared with 29 percent for white women, and 17 percent for Asian or Pacific Islander women."
"In 2011 , 72 percent of all births to black women, 66 percent to American Indian or Alaskan native women, and 53 percent to Hispanic women occurred outside of marriage, compared with 29 percent for white women, and 17 percent for Asian or Pacific Islander women."
http://www.childtrends.org/?indicators=births-to-unmarried-w...
In the US - 83% of abortions are done by unmarried women (http://www.guttmacher.org/pubs/journals/2506899.html). So it seems that marriage plays a large role here.