The contingency of monozygotic twins is four births per millennium worldwide. In contrast to fraternal twins, the monozygotic twins share 99 percent of the genetic makeup with each other. Any germline or somatic mutations in an identical twin may lead to cancer. This case study focuses on the varying effects of post-oncological treatment on fertility in monozygotic twins. Case presentation Monozygotic twins A and B were presented to the reproductive center of a hospital for primary infertility.

Twin A Investigations GTG banding (Giemsa banding) sample indicated a normal karyotype in twin A. Thus, she was treated with cytostatic as per AML-BFM 83 (AML-Berlin-Frankfurt-Munster (BFM)-83) protocol. Due to the absence of malignant cells in the cerebrospinal fluid, no radiotherapy was further performed. She underwent bone marrow transplantation (BMT); her twin sister was the donor. After…