SALT LAKE CITY — Many women cheered Thursday when they heard slacks are now a year-round option for female missionaries of The Church of Jesus Christ of Latter-day Saints, except during church services and other occasions when more formal attire is required.

The change is effective immediately in all 407 of the faith's missions, where women now comprise 27 percent of missionaries, up from 12 percent in 2012.

With that increase have come notable changes for sister missionaries. A change in a dress code may seem minor, but returned missionaries say switching from dresses to pants can be complicated, is taboo in some cultures and eventually could impact church culture.

Latter-day Saint sister missionaries will continue to wear skirts and dresses when attending the temple and during Sunday worship services, baptismal services, mission leadership and zone conferences. Otherwise, they now have a new choice.

"This is truly optional," Sister Bonnie H. Cordon, Young Women general president and member of the Missionary Executive Council, said in a news release. "The sisters can wear dresses, they can wear slacks, whatever will help them in their service as they're out amongst the people."

Summer Hopper's legs swelled up when she began serving in Guatemala in 2015 because of mosquito bites she suffered wearing dresses and skirts. She said she developed a rash and got sick.

Hopper, 22, a junior in economics at BYU, said a number of women in the mission also got sick back then. The following year, in 2016, church leaders announced that women in areas with a high risk of those diseases could wear slacks during the rainy season. For Hopper in Guatemala, that meant year-round: "We had the wet season and the less-wet season."

To her surprise, she found herself conflicted about wearing pants.

"At first, I didn't feel like a missionary when I wore pants," she said. "Obviously that's a cultural thing. Another thing is that in Latin America, it was less culturally acceptable for women to wear pants. That made some sisters hesitate."

The mission president found that sisters who still chose to wear skirts got sick more often. He counseled them to wear only long skirts, and Hopper said it "made a huge difference."

Riverton's Kate Saunders, 21, started to serve after the 2016 change but still felt sad to wear slacks.

"I grew up with the picture of sister missionaries in dresses and skirts," said Saunders, a BYU-Idaho freshman who returned in August from her 18-month mission in Tampa, Florida. "But once I started to wear slacks, it became normal. It was great because we had more options, and we could do a lot more service."

A mission president's wife said the women she worked with in the Brazil São Paulo Mission had to wear pants for four or five months a year because of the danger of disease. Still, not all liked the 2016 announcement.

"It was really hard for many of them because the image of a sister missionary has always been a woman in a dress," said Spanish Fork's Cathy Silcox, who served from July 2015 to June 2018. "Then others arrived after the change who loved the idea of slacks and were disappointed they could only wear them four or five months a year. Some welcomed the time they got to wear skirts and others looked forward to putting on those slacks again."

Bottom line, "It did cut down on the incidents of Zika and dengue," Silcox said. "It did what they wanted it to do."

Rosalynde Welch served a mission and said she now sometimes wears slacks to church as a mother and Latter-day Saint scholar in St. Louis, Missouri. She said since pants themselves have little intrinsic meaning and no moral significance, it felt petty to invest them with greater significance.

Still, Welch said the decision takes place in a larger context and that she will be interested to see if an alteration to the dress requirements for sister missionaries will trickle down to the broader church.

"As sister missionaries have become a greater percentage of the missionaries serving in the church, their needs and convenience have had a greater presence on the radar screen," Welch said. "Now a sister sits on the missionary committee and I think that certainly has made a difference."

Saunders, Silcox and Welch said slacks help sister missionaries stay warm in the cold, better ride bicycles where necessary and more easily engage when a service opportunity arises.

"Mission work is an active lifestyle," Hopper added. "Sometimes wearing a skirt makes that hard, so I think wearing pants is a great idea."