In 2011, the world’s largest sperm bank, Cyros International, briefly stopped accepting donations from men with common Scandinavian features, including red hair and light eyes, citing a lack of demand from customers. “We are very happy with redheads and what hair color people have, but our job is to supply all races, all hair colors and all eye colors and our problem is that we are located in this part of Northern Europe,” Cyros’ director, Ole Schou, told BBC News at the time. “We supply worldwide so we need more of non-typical Danish characteristics in our crops.”

Photographer Marina Rosso read about Cyros’ decision in the course of research about artificial insemination, and was intrigued by the ethical questions it inspired. “I decided to dig more into this news to understand better what was truly behind it,” she said. “In the end, what I discovered is that Cyros hasn’t got anything against redheads. It’s just a consequence of customer choice. People don’t dislike redheads; they just prefer other traits. I thought this would be interesting to show and analyze.”

For her book, The Beautiful Gene, which was published and supported by Fabrica, Rosso sought create a sort of anthropological catalog of people with red hair. She looked through the websites of several sperm banks and noted that customers can search for donors by selecting among specific features. As Rosso began her project, she constructed her own matrix of physical characteristics among redheads including eye color, hair texture, height and build and began searching for people who embodied unique combinations of those traits.

To find her subjects, Rosso attended conventions for people with red hair around Europe. Sometimes, she’d stop people with red hair in the streets to try to recruit them for her project. She also spent hours on Facebook looking through the profiles of friends and friends of friends, hoping to find redheads among them. The people she ultimately chose are from all around Europe. There are a few Americans and one Canadian in the project.

When it came to picking a look for her portraits, Rosso imagined redheads as a species to preserve. To convey this feeling, she did research on the aesthetics of how animals, including insects and birds, are cataloged. As a result, Rosso chose to photograph her subjects shirtless, straight on, and against a neutral background with a consistent lighting style.

Cryos has begun accepting red-haired donors once again, though anonymous redhead donors are still not accepted. Still, questions regarding the intersection of science and morality remain, ones that Rosso wants viewers of her work to keep considering. “I hope they will think about the boundaries of morals. How we are shifting our beliefs is a consequence of new scenarios produced by technological innovations,” she said.