As Americans discuss black livelihood in the context of recent high-profile black deaths at the hands of police officers, a merciless villain is quietly snatching away thousands of black lives each year: infant mortality. To be sure, medicine has gone a long way toward keeping black babies alive. In 1850, the black infant-mortality rate was 340 per 1,000 (compared with 217 per 1,000 for whites). Still, despite progress, last year over 7,000 black babies died in the United States before reaching one year of age — one baby for every 87 born. Troublingly, the infant-mortality rate is far higher for...