Because black people aren't more likely to go to jail when accused of a crime, which guarantees they can hold two-parent families just fine! Excellent knowledge. Luckily, people closer to poverty aren't likely to have unprotected sex at an earlier age, having children at an earlier age, which is known to be a common element to single parenting. Thankfully, though, young single parents aren't less likely to unsuccessful to have long lasting relationships that may lead to marriage and restoration of a two-parent household. Good thing the United States hasn't experienced veritable stagflation since the 60s, ensuring that two people working different shifts can make enough to manage the needs of their household without accumulating debt that could eventually deprive them of the security they otherwise had.
Of course, if any of that is wrong, your logic would be vastly flawed. So, if anyone challenges the legitimacy of your claim, here's some studies to hunt down:
Boetcher, Joseph Francis, 2009, Race stereotypic crimes and juror decision making: Hispanic, black, and white defendants, Univerity of Nevada Las Vegas.
Kirby, Douglas et al., 2001, Manifestations of Poverty and Birthrates Among Young Teenagers in California Zip Code Areas, Family Planning Perspectives, Vol33:2, p. 63-69
Kiernan, K. E., 1997, Becoming a young parent: a longitudinal study of associated factors, Department of Social Policy, London School of Economics and Political Science, Vol48:3, p. 406-428.
Qian, Zhenchao; Lichter, Daniel T.; Mellott, Leanna M., 2005, Out-of-Wedlock Childbearing, Marital Prospects and Mate Selection, Social Forces, Vol. 84:1, p. 473-491
Aratani, Yumiko; Chau, Michelle, 2010, Asset Poverty and Debt Among Families with Children, National Center for Children in Poverty