Proper nutrition in early life is also a major factor for later fertility.A study in the US indicated that approximately 20% of infertile women had a past or current eating disorder, which is five times higher than the general lifetime prevalence rate.A review from 2010 concluded that overweight and obese subfertile women have a reduced probability of successful fertility treatment and their pregnancies are associated with more complications and higher costs. In hypothetical groups of 1,000 women undergoing fertility care, the study counted approximately 800 live births for normal weight and 690 live births for overweight and obese anovulatory women. For ovulatory women, the study counted approximately 700 live births for normal weight, 550 live births for overweight and 530 live births for obese women. The increase in cost per live birth in anovulatory overweight and obese women were, respectively, 54 and 100% higher than their normal weight counterparts, for ovulatory women they were 44 and 70% higher, respectively. Radiation
Exposure to radiation poses a high risk of infertility, depending on the frequency, power, and exposure duration. Radiotherapy is reported to cause infertility,. the amount of radiation absorbed by the ovaries will determine if she becomes infertile. High doses can destroy some or all of the eggs in the ovaries and might cause infertility or early menopause. Chemotherapy
Chemotherapy poses a high risk of infertility. Chemotherapies with high risk of infertility include procarbazine and other alkylating drugs such as cyclophosphamide, ifosfamide, busulfan, melphalan, chlorambucil and chlormethine.
Sororal relationships
Various studies have shown that  older sisters are likely to give a varied gender role to their younger siblings as well as being more likely to develop a close bond with their younger siblings. Older sisters are more likely to play with their younger siblings. Younger siblings display a more needy behavior when in close proximity to their older sister and are more likely to be tolerant of an older sisters bad behavior. Boys with only an older sister are more likely to display stereotypically male behavior, and such masculine boys increased their masculine behavior with the more sisters they have. The reverse is true for young boys with several sisters, as they tend to be feminine, however, they outgrow this by the time they approach pubescence. Boys with older sisters were less likely to be delinquent or have emotional and behavioral disorders. A younger sister is less likely to be scolded by older siblings than a younger brother. The most common recreational activity between older brother/younger sister pairs is art drawing. Some studies also found a correlation between having an older sister and constructive discussions about safe sexual practices. Some studies have shown that men without sisters are more likely to be ineffectual at courtship and romantic relationships. Fictional works about sisters
Films
What Ever Happened to Baby Jane?