Zoe Eilers of St. Louis Park found lots to like about Santa Clara University, a private Jesuit school that the freshman now calls her home away from home.

Sunshine 300 days a year. An abundance of hilly running trails. A rich cultural and culinary scene, thanks to the school's proximity to San Francisco.

But the biggest selling point? Zoe is a mere 20-minute car ride, or one train stop, from her twin brother, Jackson, who just began his studies at Stanford University.

"Jackson told me to go where I wanted to go," said Zoe, who was accepted to all 14 schools to which she applied. "But I couldn't resonate with that. I'm still really protective of him."

Morgan Downing said it was "a running joke" in her family that she'd take the East Coast and her twin sister, Trianna, would take the West Coast when it came time for the Hopkins High School seniors to begin their college application process.

"Our parents said, 'Nope. Pick one coast.' "

Morgan is a freshman at American University in Washington, D.C. Trianna is 10 Metro stops away at The George Washington University.

"I don't think I ever, in my heart, believed that we would be going to the same school," 18-year-old Morgan said. "But I knew we'd be pretty close."

Pretty close is right. Picking a college can be overwhelming for high school students. Big or small? Midwest, South or one of the coasts? Liberal arts or the sciences? Generous financial aid package or hello, student loans?

But siblings such as Zoe and Jackson, and Trianna and Morgan, have an additional, sometimes aching, decision to make:

Together — or on their own?

There's scant research on the subject of college-bound twins, but no shortage of fascination at high school graduation time among family and friends regarding these unique and enviably close humans.

What are they going to do?

I've been hearing for weeks from parents of twins, including those whose kids couldn't wait to be on their own and those who couldn't bear to separate, choosing nearby schools. Sometimes they end up at the same college — or even living in the same dorm.

One mom told me that her twins, now high school seniors, don't even want to think about college because the potential split is too stressful.

"Separating is a challenge for a lot of kids," said Nancy Segal, a professor of psychology at California State University, Fullerton, who specializes in twin research. "For twins, identical twins particularly, it's doubly challenging."

And tougher, still, when one twin wants to separate and the other doesn't.

Segal, assistant director of the Minnesota Center for Twin and Adoption Research at the University of Minnesota from 1982 to 1991, said her interest in college-aged twins grew after counseling many worried parents.

Some asked her if it was preferable for their twins to attend the same school or to separate. Others wondered if applying to the same colleges would improve, or lessen, each twin's likelihood of getting accepted.

There's reason to wonder. One college administrator, for example, said that schools "often consider twins as a unit."

Other schools, though, "magnify small differences," Segal said, "causing one twin to be rejected."

Concerns don't stop there. Segal has counseled several families whose twins were accused by their college professors of cheating because their work was so similar. One set almost got thrown out of medical school.

"These families," she said, "have described the terrible strain that this imposes upon them."

Segal hopes that such stories will compel university leaders to increase education around "twins' unique circumstances."

She added, "This is a neglected, yet extremely important, area of concern."

Keeping in touch

More often, though, one of the most pressing concerns is knowing when the other twin will be free to Snapchat.

"We talk almost every day," said 21-year-old Sarah Keppeler of her identical twin sister, Jane. Both college seniors, Sarah is studying graphic design at Drake University in Des Moines. Jane is a communications major at the University of Missouri.

"Snapchat is kind of the easiest — or we FaceTime a couple times a week," said Sarah, who was heading to Columbia, Mo., for the weekend because it had been six very long weeks since she'd seen Jane.

"The longest we'd been apart before college was a week," Sarah said.

Their mom, Annie Herbert of St. Louis Park, said her girls, part of a blended clan of five children, were pretty much inseparable growing up. "They ate the exact same food — broccoli Cheddar soup every day. They would climb into two laundry baskets with pillows and watch the 'George of the Jungle' movie every day. I'd have to separate them for quiet time."

When it came time to think about college, Sarah and Jane agreed that they needed to forge their own paths.

"I don't know if we ever had a conversation," Jane said, "but we just knew we didn't want to go to the same college. We kind of wanted to do our own thing."

Still, adjusting took a while. "It definitely was weird going from constantly having someone to hang out with 24/7 to being completely independent," Jane said.

"It was exciting, too," she added. "We got to tell each other about our friends."

Being herself

Trianna Downing had a similar experience when she decided to separate from Morgan and attend George Washington. For starters, nobody at the university knew she was a twin.

"I kind of like it, being known as my own person. It's nice to be known as Trianna, studying business administration."

That doesn't mean she can't Snapchat with Morgan, a communications major, "maybe six or seven times a day," and visit her weekly.

"It's a huge connection," Trianna said, "deeper than most sisters have. I am very blessed to have her."

Jackson and Zoe Eilers' mom, Angie, also is finding comfort with her twins' decision to locate in proximity. Zoe is thinking about pre-med. Jackson is studying math.

"The only consolation of being an empty-nester," Eilers said, "is that they're so close."

When they were little, Eilers recalls, they had separate bedrooms, "but Zoe's room was untouched. She'd always go into his room. In photos, they always had their arms around each other."

Jackson and Zoe will be able to embrace again when they celebrate their 19th birthday together on Friday.

"Now that she's also in California," Jackson said, "it's going to be really nice."

gail.rosenblum@startribune.com 612-673-7350 • Twitter: @grosenblum