Their shared sense of humor sparked a friendship that blossomed, and "it just felt meant to be, with no question that it was right and the timing was perfect for both of us," Evelyn recalled.

The Clarks were involved at their church, and they dreamed of raising a family together in the town where Will grew up and where they met. Everything was falling into place: After dating for less than a year, they got engaged, and four months later they were married. They found a home in a safe neighborhood with great schools, close to relatives.

Unbeknownst to the Clarks, the road to expanding their family would be a long and grueling one-a roller coaster of heartbreak, hope, and medical intervention. Realizing their dream would require the help of a series of specialists, plus a woman who started out as a perfect stranger.

Around four years into marriage, frustrated by her inability to conceive, Evelyn submitted to a battery of invasive and uncomfortable fertility tests. Sometimes it is relatively simple to treat fertility issues. But when it is not, the results of these tests can crush patients. Unfortunately, Evelyn's diagnosis revealed an issue impossible to fix. A brusque radiologist delivered the news that she had a congenital abnormality-a unicornuate, or partial, uterus.

Would she ever be able to have children, she wondered? It's possible, he replied, but perhaps "half" as many as your friends do. Then he laughed.

The sting of the doctor's joke remains fixed in her memory years later. In a follow-up conversation with her reproductive endocrinologist, the news got worse: Her uterine abnormality meant not only that becoming pregnant would be difficult, but that any given pregnancy had just a 28 percent likelihood of ending with a live baby. She was at higher risk of miscarriage and stillbirth, but also of ectopic pregnancy-a potentially lethal condition where an embryo implants outside of the uterus.