Women describe the catalytic event as a defining moment when they choose to cross the threshold, realizing that even if they don’t know exactly what is on the other side, moving toward motherhood is better than staying in place. Moving into the liminal phase, considering single motherhood, often brings a feeling of relief.

While a woman’s age, referenced by many women as the “biological clock,” contributes to some women’s choice to cross the threshold, age is really more of a backdrop than a catalyst. Birthdays act as markers, reminding women that they are off their imagined life course. Often in conjunction with other factors in their life, age gives women a limited window for having a child, and surfaces as a trig­ger in moments of change, such as time off from work or when deciding to take a higher-powered job. There is also a social dimension to age, as women do not want to be out of sync with their friends. Women hold widely differing views on the age when they are ready to have children, but the most pressing stories are those of women who have reached age thirty-five and feel that they must decide what to do. A smaller group reaches age thirty, considers single motherhood, and sets guidelines for revising their life plan; others who arrive at thirty decide to become pregnant rapidly. Their stories reveal five types of catalytic events:

breakups, interruptions, losing a loved one, medical interventions, and cement­ing a relationship.5