Dozens of books and movies detail a future in which eugenics, in some sneaky form or another, takes over society. A master class decides which traits are desirable and slowly begins to weed out individuality, flaws, and free thought. It may have seemed like an impossible dystopian future for many of the writers who imagined it decades ago, but today reproductive and genetic technology have made such a future a very real fear for many.

The fear of designer babies may be real, but not everything people believe about them is true. Even the term designer baby insinuates vanity, suggesting a process in which couples can pick out traits for their child as easily as if they were choosing fabric samples for their home and removing entire traits or disabilities from the population. The reality behind such children is far from that flippant scenario, however: Here are four of the most common beliefs about designer babies, and how accurate they actually are.

We Can Design Desirable Embryos: False

The most persistent misconception about the medical process that produces so-called designer babies, called preimplantation genetic diagnosis (PGD), is that a scientist creates new embryos that possess certain characteristics. But PGD is a process of selection, not creation. First off, couples are always undergoing in vitro fertilization before they can choose PGD. This requires a doctor to create embryos by manually combining an egg and sperm in a laboratory dish. This is the only way an embryo is created — doctors cannot alter characteristics of the embryo before or after it is fertilized.

A clinician creates a number of embryos, then lets them develop for about three days before looking at their genes. At this point, the embryo has six to 10 cells, one or two of which can be pulled out to be tested. This is where the selection comes in — if a couple learns that an embryo tests positive for Huntington’s disease, they may choose to implant a different one.

Though the current process does not allow for modification of the embryos, The United Kingdom’s Human Fertilization and Embryology Authority recently gave British scientists the go-ahead to genetically modify human embryos for research purposes. The U.S. has not made any moves to allow this, but British experts seemed happy with the ruling.

“This decision … is a victory for level-headed regulation over moral panic,” Sarah Norcross, director of the Progress Educational Trust, told CNN.

We Can Reduce Certain Disabilities In The Population: True

One of the most popular uses for PGD is screening embryos for genetic disorders. Couples who discover they carry sex-linked or single-gene genetic disorders often opt for PGD to avoid having a child with that disease. Doctors can screen for over 100 different conditions, including many that severely cut down the quality and length of life, such as Tay-Sachs disease, which usually kills children by the age of four, and Huntington’s, hemophilia, cystic fibrosis, and sickle cell disease. They can also test for chromosomal abnormalities, where a cell has too many or too few chromosomes, such as Down’s syndrome.

Theoretically, couples can choose an embryo with one of these conditions, but most of the time partners go through PGD to weed out disabilities.

Many have questioned whether the process promotes prejudice against disabled people. While this is a controversial claim, PGD does have the potential to decrease the number of people with genetic disabilities in the population depending on who decides to use it and how.

Couples Can Choose Cosmetic And Personality Traits: False

One of the scariest thoughts about genetic testing focuses on the idea of choosing “desirable” traits over others, which could eventually lead to a more homogenous population. Given the choice, wouldn’t any parent choose for their child to be intelligent? What about tall or athletic? Plucking nice traits out of a brochure for a child, in theory, would almost certainly reshape the population, but technology simply isn’t capable of it.

The only relatively cosmetic traits a doctor can screen for right now are sex and eye color. It’s relatively straightforward to select an embryo of a certain sex once they have been tested, and certain gene variants can predict eye color with great certainty. Past this, the waters are murky. Hair color is still mostly a genetic mystery, and less-defined traits — a small nose, for example — are impossible to screen and will likely remain so for many years. As for personality traits like intelligence? Forget about it.

Still, many have worried that sex selection and a preference for boys could create problems in society. But as with disability screening, the number of potential parents using PGD at this point is not enough to allow the manifestation of gender preference and change the population.

Only Some Can Afford PGD: True

One of the main reasons that fears over a PGD baby takeover are unfounded is the costliness and difficulty of the process itself. In vitro fertilization with PGD and a subsequent embryo transfer costs about $17,000 to $25,000 in the U.S. Almost all health insurance plans refuse to cover PGD, as it is considered experimental or not medically necessary. Most couples cannot afford such a financial burden — and if they can, they are not likely to waste time and money sifting through embryos for something so trivial as eye color.

The process is nothing to scoff at scientifically or medically, either.

“There is a general misconception that the whole embryo biopsy process is just another ‘option’ in the IVF/embryo transfer menu,” Dr. Michael Trucker, Scientific Director and Chief Embryologist at Georgia Reproductive Specialists in Atlanta told FertilityAuthority. “The most important thing to remember about PGD is that it is an invasive technology. At least one cell or more must be removed from each embryo to enable the assessment to take place, and as such it is not a procedure that should be undertaken lightly.”

Preimplantation genetic diagnosis has been, and will most likely remain, controversial for many reasons. Ethical dilemmas and fear of prejudice usually top the list of concerns, but advocates for PGD point out that the procedure has likely saved many children from living short, painful lives with diseases that could have been prevented. Whether or not society allows certain forms of PGD, one undeniable truth is that the technology is improving every day.