Medical and Science Communities Could Take a Blow From Trump's Immigration Order

— -- Several members of the science and medical communities are warning that Donald Trump’s executive order to largely ban travelers from seven majority Muslim nations will likely wreak havoc on universities, students and professors in the coming weeks, as well as the U.S. medical field, which relies on international doctors to fill significant gaps.

The Association of American Medical Colleges released a statement saying they are "deeply concerned" about the order's effects.

"The United States is facing a serious shortage of physicians," the AAMC said in the statement. "International graduates play an important role in U.S. health care, representing roughly 25 percent of the workforce."

One medical resident based in Brooklyn has been unable to return home from a trip to see family in Sudan, according to officials at Interfaith Medical Center in Brooklyn, NY. It was the first time in two years he went home, according to LaRay Brown, President/CEO of the medical center.

Brown said Dr. Kamal Fadlalla told her that he tried to board a plane back to the U.S., but was turned away.

"We are committed to him," Brown told ABC News. "We want him back."

Brown said they want to hold Fadlalla's residency spot, but that it will likely create hardship on other physicians who pick up his cases while he remains stuck in Sudan.

Medical students also face disruption. In scientific fields, doctoral and post-doctoral students often spend years working on lab research before applying for competitive professorships at various institutions. The key months for interviews in those positions are January and February. Medical students who apply to residency in the fall are matched with an institution in March. Now institutions must consider whether or not to admit those applicants who no longer have valid visas to enter the U.S.

The current executive order could mean students, who have spent years in the U.S., face diminished chances of acceptance.

Joshua Plotkin, Professor of Biology at the University of Pennsylvania, said one post-doctoral student in his lab was stranded abroad in Europe when the executive order was implemented and could risk missing key interviews in the coming weeks. Plotkin said the student wished to remain anonymous at this point.

"They are separated from their home and spouse and their job and what's really heartbreaking for me, they have several faculty job interviews," Plotkin explained.

He said these interviews are the result of years of research and study.

"The issue is the faculty jobs in science are so competitive and rare," Plotkin explained. "The same person trying to get in next year is very likely to have completely different outcome."

Plotkin said that the student, who was born in Tehran and educated in Europe, is married to a U.S. citizen and holds a green card. While a waiver will reportedly allow green card holders to enter the U.S., Plotkin said lawyers have advised the student to wait until they have more guidance and can be assured the student would not be sent to Iran if they showed up at a U.S. border office.

President Trump's executive order, which he said is aimed at protecting the nation from terrorists, suspends for 90 days immigration to the U.S. from seven countries -- Syria, Yemen, Sudan, Somalia, Iraq, Iran and Libya. It also suspends for 120 days the entry of refugees into the U.S. and indefinitely bans Syrian refugees from coming into the country.

The Educational Commission for Foreign Medical Graduates said they are "in the process of evaluating the potential impacts of this order."

Many in the scientific community point out that the ban could mean losing highly educated students who may have spent years at U.S. institutions, which devoted resources to their work.

Jen Golbeck, Ph.D and associate professor of Computer Science at University of Maryland, started an online database to connect people stranded abroad with others willing to help. She said knows of one Florida student from Iran, who was stranded in England after his student visa was no longer valid in the U.S.

"The impact it's going to have on academics in the U.S. is chilling," Golbeck said. "It's been a scientific leader for decades not because we're smarter, but because we draw best minds to universities."

She and others have been trying to find another lab potentially willing to help the student, who has decided to remain anonymous, continue his research in the event he can no longer come back to the U.S.

Hazhir Rahmandad, an associate professor of System Dynamics at M.I.T., said the ban could affect the scientific communities in profound ways in years to come.

"A lot of people going for Ph.D. programs and graduate admission," Rahmandad said, "are very likely not be able to come to U.S., even if we admitted them."

"Going forward we would not hear from many of these applicants," he said.

Rahmandad said he has one student affected by the ban, who is unable to leave and whose family will likely be unable to visit if the ban remains in place.

"We are losing a lot of talent and potential collaborators, who cannot work with us because they cannot join our team or come to conferences here, and we can't retain talent," he added.

Priya Raja contributed to this story. She is a Medical Fellow in the ABC News Medical Unit as a part of the Stanford - ABC News Global Health and Media Fellowship. She is also a rising third year medical student at The University of Texas Southwestern Medical Center.