A considerable number of women with breast cancer are diagnosed during their reproductive years. In the short period of time in which newly diagnosed women will need to make decisions about surgical options and adjuvant therapy, younger women with breast cancer also face the potential impairment or complete loss of their fertility. The preservation of fertility should therefore be an integral consideration in the choice of breast cancer therapy. Preserving ovarian function is particularly challenging for women with estrogen receptor-positive tumors, as the suppression of ovarian function has been shown to be beneficial therapy with regard to breast cancer outcomes. The current emerging recommendations of hormonal therapy extending to a 10-year period will likely further impact the timing of any subsequent pregnancy or require an interruption in hormonal therapy. To optimally counsel patients on how to best weigh the risks and benefits of each intervention, both the care provider and the patient must understand the options and the likelihood of their success. Here we summarize the current challenges and options for women diagnosed with breast cancer who wish to preserve their fertility.