News at a glance

In science news around the world, the next target for Pluto-observing spacecraft New Horizons might be two objects rather than just one, the U.S. Food and Drug Administration sends a letter warning of regulatory violations to the fertility specialist who created the first baby using controversial mitochondrial replacement therapy, Berlin scientists learn that sick squirrels in the city have a new form of poxvirus, Italy and France both make some vaccines mandatory for school-age children, and more. Also, a Chinese biologist whose team last week retracted a high-profile paper on a gene-editing technology defends his work.