Katherine Calvo, M.D., Ph.D., 43, son Sean, 17, and daughter, Leah, 15, finish packing up the family home in La Jolla, Calif., to relocate Katherine and Leah to Bethesda, Md. (photo courtesy Katherine Calvo) RELATED LINKS How to Take a Radical Sabbatical Personal Coach: What's Holding You Back? Radical Sabbatical Story Index Radical Sabbatical TV Series

By Bill Spring

When Dr. Katherine Calvo was a girl, her idols were Madame Curie and Mother Teresa, illustrating a belief that the world's ills could be solved by a combination of scientific advancement and selfless personal sacrifice.

Today, Calvo, 43, is an accomplished medical researcher fully entrenched in the battle against cancer. But getting to this point meant facing the possible death of her young son.

Calvo grew up in the Chicago area during 1960s. "When I was in the fourth grade, I wanted to be a biochemist," she says. "I was always strongest in math and science."

But swayed by the popular idea that science wasn't a proper pursuit for a young woman, Calvo veered onto a new path, majoring in International Studies in college.

Shortly before graduation in 1985, she married Ahmed Calvo, who had just finished his medical training. With the arrival of their son Sean in 1986 and daughter Leah in 1988, Calvo set aside plans to attend law school and embraced life as a full-time mother while Ahmed practiced medicine in the San Francisco area.

Yet it was pregnancy and parenting that led her back to biochemistry.

Calvo began reading her husband's medical texts to learn about the changes taking place in her body during pregnancy. She engaged him in long talks about his work. "In the course of having my two children, I decided that I loved science, and I wanted to go back to school and become a doctor."

Few people thought that a mother of two in her thirties could possibly get through medical school. "The more I heard (the push back)," she explains, "the more I thought, 'I'm going to do this.'" Her husband initially feared that the grind of med school could break their relationship, but he eventually gave his wife his full support. She began taking pre-med classes at Stanford in fall 1990.

During spring break in 1991, the Calvos noticed something was wrong with 4-year-old, Sean. "He said that his legs were hurting him, and he wanted me to carry him everywhere," she remembers.

Ahmed noticed a suspicious bruise on Sean's shoulder and took the boy in for a blood test. The test showed that Sean's white blood cell count was three times higher than normal, suggesting leukemia. A bone marrow biopsy soon revealed that the cancer had already taken over 95 percent of Sean's marrow.

"My stomach just dropped when I heard the news, " Calvo recalls. "I remember thinking, 'How can this be?' " Within hours of the diagnosis, Katherine and Ahmed committed Sean to an aggressive, experimental chemotherapy program, and the treatment began.

Chemotherapy was a very tough fight for Sean, and Calvo considered abandoning her studies. "I was faced with the fact that my son might die, and I remember feeling that I should give everything else up," she says.

Ironically, it was Sean's oncologist who told her to continue taking classes. "He felt that it was very important for me to keep pursuing my dreams," she remembers. He said that parents who give everything up are the ones who don't deal with death or the hardships of chemotherapy very well. Calvo continued at school, but cut back on her classes.

By 1994, Sean was done with chemotherapy and was regaining his health. At the same time, Calvo had finished her pre-med classes and had been accepted to medical school at the University of California, San Diego. Her husband agreed to leave his successful practice and the whole family moved south.

While he worked on establishing a new practice and the kids adjusted to new schools, Calvo threw herself into her new life as a full-time med student. She also helped establish the school's first student-run free clinic.

During her second year, Calvo was accepted into the elite Medical Scientist Training Program, which requires earning both an M.D. and a Ph.D. A rotation in a leukemia research lab and her attraction to cutting-edge science led her to choose leukemia as the subject of her doctorate thesis project.

Calvo went from holding her weakened son's hand as he endured leukemia-fighting treatment to a far more clinical and scientific relationship with the disease.

Sean Calvo, now 17, has been in full remission since ending treatment in 1994. His childhood fight with leukemia, along with the examples set by his parents, have inspired him to become a pediatrician. Leah, 15, has also expressed interest in pursuing medicine.

This spring, Calvo finished the nine-year Medical Scientist Training Program and accepted a residency at the National Institutes of Health in Bethesda, Md., where she will work on developing cures for cancer.

"They're giving me lab space and letting me pursue my research," she says. "It's a dream come true."