BOSTON — Who's better at getting a family to talk about money matters, mom or dad? Taking sides probably won't make for a harmonious Mother's Day celebration on Sunday.

Yet a survey by a financial services company found that mothers clearly have the upper hand over fathers in getting the discussion started with their adult children. While all families are different, moms are often the ones who encourage conversation about such important topics as financial security in retirement, caring for an elder and estate planning, according to survey results released Tuesday by Fidelity Investments.

"Moms are more likely and open to having deep, detailed discussions," said Lauren Brouhard, a senior vice president for retirement with Fidelity's personal investing business.

"Starting the discussion with mom may be a good strategy," given how awkward such conversations can be, Brouhard said.

Key findings from the Boston-based company include:

—Seventy percent of the mothers aged 55 and older who were surveyed reported they'd had comprehensive discussions with their adult children about their ability to cover living expenses in retirement. Just 55 percent of fathers had talked about that topic.

—Seventy-nine percent of the moms had discussed estate planning or wills with their adult children, compared with 69 percent of fathers.

—Sixty-six percent of mothers had discussed health topics such as caring for elders, while 56 of the dads had done so.

—Sixty-four percent of mothers said it is "not at all difficult" to start a conversation with an adult child about savings and investing, versus 54 percent of fathers who said that.

One reason that mothers were more open to discussing such matters: They were more likely to describe themselves as the "the empathizer" in their families. Fifteen percent of moms said that was the case versus 6 percent of fathers describing themselves that way. Fathers were more likely to view themselves as "the pragmatist" in discussing finances, believing they take a more straightforward approach than mothers.

When asked privately about these hard-to-discuss topics, survey participants offered widely varying views on whether their families were discussing money matters in sufficient detail, if they were having the conversations at all.

In many instances, adult children who participated in the surveys "felt that the conversations were not happening at the level of depth required," Brouhard said.

"What's really important is that these not just be surface discussions. Nobody wants surprises down the road, so it's important that they have these conversations now, when they're not reacting to some financial or health emergency."

The survey was conducted from July 24 to Aug. 29 by the firm GfK, with Fidelity not being identified to survey participants as the sponsor. GfK used its KnowledgePanel sample, which first chose participants for the nationwide study using randomly generated telephone numbers and home addresses. Once people were selected to participate, they were interviewed online. Participants without Internet access were provided it for free.

The total sample recruited for the study included 975 parents who were 55 years or older, had an adult child and investable assets of at least $100,000.