(CNN) Decades ago, newly married women overwhelmingly would adopt their husband's last name, satisfying a social custom and securing certain legal, economic and familial protections.
In some states, those safeguards included being able to retain their driver's license or voter registration, pick up their children from school, or have a credit card, said Stephanie Coontz, the director of research and public education for the Council on Contemporary Families.
Culturally, adopting the husband's name was connected to paternalistic notions of ownership -- women once belonged to their father, then their husband, said Deborah Carr, a professor of sociology and director of the Center for Innovation in Social Science at Boston University.
Despite a growing feminism movement and increased gender equality, the overwhelming commonness of this practice remains. Contemporarily, "at least in the US, about 20% to 30% of women retain their name, meaning the vast majority take their spouse's name when they marry," Carr said. That includes artist Jennifer Lopez, who recently confirmed her marriage to actor Ben Affleck with the signature "Mrs. Jennifer Lynn Affleck."
"Women may take their husband's name legally," Carr said, "but professionally, I would bet she will continue to perform under the name of J. Lo. Sometimes people take their husband's name legally, but professionally, they may still use their maiden name."
It wasn't until legal changes and a booming feminist movement in the 1970s that there was a big push to keep one's last name, Carr said. That tendency dipped during the 1980s, a more conservative era, and has fluctuated since the 1990s, she added.
The decision to retain or forgo one's name can still be influenced by economic, familial, social, romantic and religious factors -- especially when children are involved.
For some people, adopting a spouse's name is a "public statement to the world that you are, in fact, a couple," Carr said. "I think the other is social pressure. It may come from the spouse, but it might come from family. And women will often get pushback -- whether from their parents or their in-laws -- about why you're not taking the name. Some people believe it means that you're not as committed to the union."
Inertia or tradition are other reasons, Carr said. "Some things have just always been done, and so people don't question them. They don't counter them," Carr said. "It's kind of the path of least resistance."
Some people might be keen to get rid of their family name because of a desire to somehow separate themselves from their biological parents, said Joshua Coleman, a psychologist in private practice in Oakland, California, and a senior fellow with the Council on Contemporary Families.
"Somebody who wasn't close to their parents or felt hurt by them (and) didn't really like being identified as a Smith or a Jones or whomever, would welcome the idea of a new surname that wasn't their own," he added.
Women who believe in gender equality yet take on their husband's name might think that the name change doesn't mean they are ceding away any of their authority as a woman, Coleman said.
"The woman doesn't see herself in some kind of subordination to the husband or ceding any of her power or authority or identity or individuality. She likes the tradition of it, but that doesn't mean that she buys into all of the things that may have gone with it traditionally," he added.
Very rarely does a husband adopt his wife's surname. In a 2018 study of 877 men, 3% (27 men) had changed their name once married. Of those 27 men, 25 had dropped their last name entirely; two hyphenated their name. Men who changed their name in any form were more likely to be less educated.
"That's probably some kind of a persistence of misogyny or patriarchy or something in that camp -- that the idea of a man taking on his wife's last name would be somehow considered problematic," Coleman said.
There isn't much research about marriage-related name changes among couples on the LGBTQ+ spectrum.
"I think part of the reason there isn't that much data is because legal same sex marriage is still pretty new," Carr said. "I suspect they may be more likely to hyphenate or to come up with something because of this egalitarianism that tends to happen -- you don't have this gendered history here."
Among the 20% to 30% of women who don't follow tradition, the most common practice is keeping their own surname, followed by hyphenation, making a hybrid name or, even more rarely, coming up with a totally new shared name, Carr said.
For some women, keeping their surname is preserving the personal and familial identity they have always had, Carr said. "That could be tied to their parents, tied to their ethnic or racial heritage -- names are very meaningful."
Practically, some people have established a professional identity, especially those in very visible positions such as writers, academics or celebrities. If their name is key to their profession, that's something they might not be willing to give up, she added.
Keeping one's surname can also be a political act, often done by those who adhere to feminist beliefs and practices, Carr said -- such as independence and equal partnership. Some question why one name should take privilege over the other, and if using just one spouse's name would convey an unequal partnership.
The prevalence of retaining one's last name is greater among women with higher levels of education and older women, Carr said. "They have more professional identity built by that point," she said, whereas younger women have fewer professional ties and might be more susceptible to family pressure.
Having children can complicate things.
"It's very rare that both partners would choose the woman's name," Carr said. "Overwhelmingly, if they choose one name, it's the one that belongs to the husband."
Many believe that using one spouse's last name is easier socially and legally, Carr said.
"People know what to call you," she said. Using one name can also prevent "administrative headaches" that can come up when it comes to things like booking flights, insurance, health care and who's allowed to pick up a child from school, she added.
Parents who don't use one surname for the entire family "have to do a lot more work and a lot of explanations," Carr said, "because a lot of our structures are not set up to accommodate innovating naming practices."
The decision to use the husband's name sometimes derives from the fact "that there's maternal certainty," Carr said. "We know who gives birth, but there's not always paternal certainty. And given that nonmarital births are still stigmatized, I think, historically, that's a reason why the couple would go with the male name."
Combining surnames in some fashion can be a way of preserving one's identity as a member of their original family and as an individual, while also having an identity as a member of a new family, Coleman said.