As Gov. Tim Walz of Minnesota has introduced himself to Americans through stump speeches across the country in recent weeks, he has alluded to a journey through infertility for his family while warning that conservatives want to restrict in vitro fertilization.

“Even if we wouldn’t make the same choice for ourselves, there’s a golden rule: Mind your own damn business,” Mr. Walz said on the night that Vice President Kamala Harris introduced him in their first joint rally in Philadelphia. “Look, that includes I.V.F. And this gets personal for me and my family.”

Many have assumed that his family relied on I.V.F. to conceive their two children. Several news outlets, including The New York Times, The Associated Press and The Minnesota Star Tribune, have reported that the family relied on in vitro fertilization. Fertility advocates concluded as much after hearing Mr. Walz talk. In April, the Tim Walz for Governor campaign office mailed out a fund-raising letter in an envelope that read: “My wife and I used I.V.F. to start a family.’’

But when asked if the Walzes wanted to share more details about their effort to conceive, the Harris-Walz campaign recently clarified that the couple did not rely on I.V.F. but rather another common fertility procedure called intrauterine insemination, or I.U.I.

The treatments have a key distinction: Unlike I.V.F., I.U.I. does not involve creating or discarding embryos. And so anti-abortion leaders are not trying to restrict the treatment.

But for people having trouble getting pregnant, the procedures are often linked. Some patients say they are “doing I.V.F.” as a catchall phrase for a wide range of fertility treatments. Mr. Walz has said that he and his wife spent seven years trying to have children.