|Estrogen is the major female sex hormone secreted primarily by the ovaries and in small amounts by the adrenal gland. It plays an important role in the onset of puberty, development of secondary sexual characteristics, such as breasts, and pubic and armpit hair. Estrogen also helps regulate the menstrual cycle and also controls breast changes during pregnancy.Scholarly peer review is the process of subjecting an author's scholarly work, research, or ideas to the scrutiny of others who are experts in the same field, before a paper describing this work is published in a journal. The work may be accepted, considered acceptable with revisions, or rejected. Peer review requires a community of experts in a given (narrowly defined) field, who are qualified and able to perform reasonably impartial review.