An executive order signed by President Donald Trump on Friday bars citizens of seven countries from entering the U.S. for 90 days. An estimated 218 million people from majority-Muslim nations are affected by the ban, according to data from the World Bank. North Texas doctors and scientists are concerned that the policy could have far-reaching effects for the health of Texans.

Texas has a doctor shortage. The state has 177 doctors for every 100,000 people, compared with the national average of 236 doctors, according to a report published in 2015 by the North Texas Regional Extension Center. That ratio puts Texas at No. 45 on the national list of doctors per person.

The state is not producing enough doctors to keep up with its growing and aging population. Trump's executive order could worsen the doctor shortage.