A Fitter Families for Georgia event in 1924. Such eugenics-oriented competitions reportedly began and spread through the United States in that decade. (Courtesy of American Philosophical Society/American Eugenics Society Records)

What if you could engineer the perfect baby?

Would you, if you could?

A century ago, a group of American scientists and reformers thought it was possible — and desirable. Their perfect baby was white, able-bodied, Christian. And the cause they embraced, eugenics, was used to justify incarceration, sterilization and even murder.

“The Eugenics Crusade,” on American Experience on PBS stations at 9 p.m. Tuesday, tells the movement’s sordid story.

A dangerous cocktail of pseudoscience and real science set the stage for the eugenics movement’s popularity. As genetic science progressed at the turn of the 20th century, some scientists embraced the theory that things like a person’s tendency to criminality was passed down from their parents. Reformers loved the idea that poverty, crime and deviance of all stripes could be bred out of future children.

Soon, the concept was used to support everything from immigration restrictions to “fitter family” competitions. Forced sterilization and institutionalization of people who were disabled, mentally ill, or thought to be sexually deviant or morally lacking followed.

Wide-ranging and sobering, the documentary highlights the movement’s uncomfortable modern remnants. Take the term “moron” — it was once used to justify selective breeding.

The film also resurrects the largely forgotten story of Ann Cooper Hewitt, an heiress who was sterilized without her consent during an appendectomy. Cooper Hewitt, who had been a minor at the time of the operation, sued her mother, claiming she had orchestrated the sterilization to get her inheritance. The trial, which pitted a white, rich and attractive woman against her mother, attracted public attention in a way the majority of sterilization’s victims never could.

Scientists eventually changed course on eugenics. But by then, the damage was done. The documentary, which was written and directed by Michelle Ferrari, shows how the movement became mainstream. Eventually, it spread elsewhere, including Germany, where it influenced Nazi Party leader Adolf Hitler and set the stage for the Holocaust. But in its American incarnation, the film suggests, the eugenics movement was perfectly commonplace. What seems obviously evil today once seemed desirable, ordinary — to everyone but its victims.