Doctors can you tell me when should young women start to have a screening of mammogram done for breast cancer?

Depends: Usually have yearly physical examinations age 20-40 and start yearly mammogram about age 40. Depends on family history & risks for breast cancer. Notify your doctor if you feel any breast lumps.

Mammograms: According to the American Cancer Society, American College of Radiology, and others, annual screening mammography should begin at age 40. Screening may begin sooner if you are a BRCA carrier or are otherwise at high risk.