Republican vice presidential candidate JD Vance on Tuesday tried to paint his Democratic opponent Tim Waltz as a liar after he misstated his wife’s method of getting pregnant. The Democratic VP candidate and Minnesota governor has championed reproductive rights as part of the ticket’s campaign platform, revealing the pain he and his wife Gwen Waltz endured through their years-long fertility struggle — but didn’t get the terminology right. “Today it came out that Tim Walz had lied about having a family via IVF ,” wrote Vance on X Tuesday.

“Who lies about something like that?” Walz and wife Gwen Walz had used intrauterine insemination, or IUI — not in vitro fertilization, commonly known as IVF. IUI involves delivering a concentrated dose of sperm directly into a woman’s uterus during ovulation, a method also known as artificial insemination. IVF entails harvesting a woman’s eggs, combining them with sperm and creating embryos in a lab , which are then implanted.

If IUI fails, couples often turn to IVF to conceive. When asked for specifics, Gwen Walz clarified she had not had to take the further step of IVF. Nonetheless, the road to conception was “ an incredibly personal and difficult experience ,” she told CNN.

Amanda Zurawski, who told Democratic National Convention-goers on Monday night about her own brush with death during an unviable pregnancy, said “ it’s absolutely disgusting ” to imply the Walz’s road was less painful than others’ que.