LONDON — It was quite the journey for such tiny froglets: traveling thousands of miles from the forests of southern Chile to London, carried and brooded inside their fathers' vocal sacs for safety.

2 Department of Obstetrics and Gynecology Mount Sinai Hospital, Toronto, ON, Canada 3 The Prenatal Diagnosis and Medical Genetics Program, Mount Sinai Hospital, Toronto, ON, Canada 4 Department of ...