Jennifer was diagnosed with leukemia last March and underwent a bone marrow transplant from an anonymous donor three months later. She's now a survivor, and Nestor is using his platform as operator of radio station WNST in Baltimore to encourage people to register to become bone-marrow donors.
"We're just beginning," Nestor said. "This is just our fun idea to build awareness for it."
According to Delete Blood Cancer, the organization that provides swab kits for the Aparicios' tour, six out of 10 people do not receive a bone-marrow transplant. Odds are lower for people of color.
While Jennifer was recovering from her operation, Nestor devised their travel schedule, which concludes July 14 in Cincinnati. That night, she'll cross attending the All-Star Game off her bucket list.
Several prominent sports figures, including Jack Harbaugh, father of Michigan football coach Jim Harbaugh, have met with the Aparicios during their journey.
"We're a little tired," Jennifer said, "but we're trying to pay it forward. Someone saved my life, and hopefully we'll be able to save somebody else's."
The tour continues Monday in Toronto.
Alejandro Zúñiga is an associate reporter for MLB.com. Follow him on Twitter @ByAZuniga. This story was not subject to the approval of Major League Baseball or its clubs.