This photograph of Mina Weil was most likely taken around the time of Gertrude's parents' marriage in 1875. Mina was born in 1859 to Emil and Eva Rosenthal, who, like the Weils, were Jewish immigrants from Germany. One of Mina's earliest memories was of her parents' sorrow as they broke the dietary laws of kashrut by eating ham to keep themselves alive as they fled Union troops during the Civil War.

Enrolled at the Wilson Collegiate Seminary for Young Ladies, Mina Rosenthal was an eager student. In 1870, at the age of 11, she earned a "Certificate of Praiseworthy Diligence and Success" in Greek and Roman history, algebra, geography, mathematics, and arithmetic. She also knew German and some Hebrew and, according to the family's biographer, had ambitions to study medicine.

At the age of only 14, Mina became engaged to the 27-year-old Henry Weil, a frequent visitor to the Rosenthal household and a member of one of the few other Jewish families in the area. With her parents insisting she finish her education before marrying, Henry and Mina put off their wedding until a few months after Mina's sixteenth birthday. Although Henry was sympathetic to Mina's professional ambitions, the couple soon had the first of their four children, and like many women of her time, Mina's life became focused on her family and service to her community.

In 1881, Mina's father, Emil, joined the Weil brothers' firm. A wise and pious man, Emil was an important figure in the foundation of Goldsboro's Congregation Oheb Sholom in 1883. Gertrude remembered her grandfather as "a decided individualist who didn't try to be different, just himself." She was also very close to her grandmother, to whom she wrote numerous letters when away at high school and college.