Colleague relationship. Tu Rui and Tu Zengrong are two doctors in the reproductive department of the First Hospital of Shanxi Medical University. Although the two medical staff have the same surname, they are not family members, but just colleagues. Tu Rui: good at male pre-pregnancy examination, male infertility, oligospermia, asthenospermia, azoospermia, hemospermia, semen liquefaction, male erectile dysfunction and premature ejaculation treatment; Tu Zengrong: He is good at reproductive immune center, infertility diagnosis and treatment, and is proficient in modern assisted pregnancy techniques such as artificial insemination and IVF.