Is Texas Sen. Ted Cruz eligible to be president of the United States? That's not a question a presidential candidate wants to be facing with just weeks to go before the first nominating contests.

And yet, despite Cruz’s success in the polls, both nationally and in Iowa, he can’t seem to avoid the question from Republican front-runner Donald Trump. Cruz has long faced doubts about his status as a “natural-born citizen,” which is a constitutional requirement for the presidency. He was born in Canada to a Cuban father and an American mother. Because his mother was a natural-born citizen, most legal scholars say Cruz is one, too.

Still, Trump has repeatedly raised doubts about whether Cruz’s mother’s citizenship qualifies the candidate to be president, and has warned that the situation would result in a legal battle should Cruz become the GOP nominee.

So who exactly is Ted Cruz’s mother, and how did she end up living in Canada? The Texas senator’s mother, Eleanor Darragh, was born to a Irish-Italian family in Delaware and was the first in her family to attend college, the National Journal reported in June. She worked as a computer programmer in New Orleans and Texas, and married Rafael Bienvenido Cruz, a mathematics graduate, in 1969, according to a big story published Wednesday in Maclean’s, one of Canada’s top magazines. Cruz’s parents moved to Canada to process seismic exploration data for oil companies in Calgary, and he was born there in 1970.

By 1974, the family moved back to Houston. The Texas senator, born Rafael Edward and called “Felito” — or little Rafael — in his early years, changed his name to Ted at age 13.

Rafael Cruz, now a pastor, has made a number of public appearances in recent years and has sometimes caused controversy with his comments about same-sex marriage. But Cruz’s mother, now in her 80s and still living in Houston, according to Maclean’s, is less known. The senator has described his mother as a strong woman, once telling a crowd that she refused to learn how to type so her male colleagues could not force her to do their typing for them. When men would ask her to type up their notes, National Journal reported, she would reply: “I would love to help you out, but I don’t know how to type. I guess you’re go­ing to have to use me as a com­puter pro­gram­mer in­stead.”

Cruz’s supporters aren’t necessarily buying the Donald’s critiques, but it does appear that many Americans are curious about the Texas senator’s family history. Questions about Cruz’s citizenship and his mother dominated Google’s top trending questions Thursday night ahead of the sixth Republican presidential debate.

While some more establishment Republicans, such as former presidential candidate Mitt Romney, have said Trump’s questions are unfounded, the issue doesn’t look like it’s going away any time soon.