Millions of Americans are getting vaccinated against Covid-19 every day, and millions more are clamoring for the sometimes hard-to-find appointments. But one group in particular isn't feeling as confident about the shots: parents.

Researchers from Northwestern, Harvard, Northeastern and Rutgers Universities surveyed nearly 20,000 parents between February 5 and March 1. The survey found that parents showed more reluctance to get the vaccine, both for themselves and for their children, than adults without kids. The results held true across different demographics and socioeconomic backgrounds, but the trend was most notable among younger moms.

About a third of moms between 18 and 35 years old expressed uncertainty about getting the vaccine—and another third said they were very likely to refuse it altogether. Moms in general were also more skeptical about the vaccine. Only about 44% of mothers surveyed said they were likely to vaccinate their kids, compared to 64% of fathers who said they would.

Though vaccines have become somewhat of a politicized issue, the results didn't vary much across political parties or even geographic locations.

The age of their children didn't change parents' thinking much either. Those with kids 12 and under had about the same level of hesitancy as those with teens.

Right now, the Pfizer vaccine is the only one authorized for teens as young as 16. Vaccines for younger children aren't yet available, and likely won't be for several more months. Dr. Anthony Fauci has estimated that the timeline for vaccines for kids could be somewhere between this fall and early 2022.

Several vaccine makers are now conducting trials involving babies and children, but researchers say the results of the survey show that there's lots of work to do to make parents feel comfortable with the thought of vaccinating their kids. "It makes clear there is a need to understand the concerns that drive the hesitancy and try to alleviate them," said James Druckman, one of the political scientists behind the survey.

If you have questions about the vaccine for yourself and your children—your best bet is always to talk to your doctor. The best choice for your family is an informed one.