Actually, the take away from this experiment is not that 'designer babies' are becoming more likely. In fact, when the researchers tried to genetically add synthetic DNA to the male genome it ended up rejecting it and took the copy from the female genome.

>> They injected a synthetic healthy DNA sequence into the fertilized egg, expecting that the male genome would copy that sequence into the cut portion. That is how this gene-editing process works in other cells in the body, and in mouse embryos, Dr. Mitalipov said. Instead, the male gene copied the healthy sequence from the female gene. The authors don’t know why it happened.