The black marriage rate has declined precipitously in the past half century. A gap has opened between black and white marriage rates which was not true two generations ago. Similarly, a gap has opened between the out-marriage rate (that is, marrying outside their race) of black women and black men, which was not true two generations ago.
Banks' main conclusion is that the imbalance in the relationship market is the main culprit. There are many more black women ready for marriage than there are black men. This lets black men, as a group, get the benefits of marriage, including children, without the obligations.
Banks concludes that if black women were more willing to marry out, the power balance would become more even. In the end, more black men and women would marry each other.