If your teenage daughter suddenly declares herself transgender, should you assume she’s mature enough to make decisions that will permanently affect her health, fertility and future? Or could she be influenced by societal and peer pressure? Physician and researcher Lisa Littman doesn’t have the answer, but transgender ideologues are trying to silence her for even asking the question.

Dr. Littman’s study about transgender-identifying teens was published in the open-source, multidisciplinary scientific journal PLOS ONE last...