Five years after they got married, high school sweethearts Aly and Josh Taylor felt ready to grow their family. Aly had read that sore breasts could be a pregnancy symptom, so she examined her own, hoping she was pregnant. During the exam, she felt a small lump.

Because she was so young, she assumed it was nothing to worry about. But she got it checked out to be safe. After a biopsy in her Louisiana hometown, she was diagnosed...