Skeptics are standing athwart the transgender movement, yelling stop, as a new study shows sex-reassignment surgeries are on the rise.

The number of procedures, including the removal and construction of external genitalia, increased nearly fourfold from 2000 to 2014, according to the study published Wednesday in the journal JAMA Surgery.

Joseph Backholm, president of the Family Policy Institute of Washington, said there is “no conclusive evidence” that these procedures lead to beneficial outcomes for transgender patients.