Boys with older sisters were less likely to be delinquent or have emotional and behavioral disorders. 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 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. 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 sister's bad behavior. Older sisters are more likely to play with their younger siblings. 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. This has been hypothesized as being attributed to the pheromones in their brothers' sweat and household-related errands. A study in Perth Australia found that girls having only youngers brothers resulted in a chastity effect, losing their virginity on average more than a year later than average. Males with a twin sister sometimes view her as their female alter ego, or what they would have been like, if they had two X chromosomes. In response, in order to avoid equivocation, some publishers prefer the usage of female sibling over sister. In some quarters the term sister has gradually broadened its colloquial meaning to include individuals stipulating kinship. In some cultures, sisters are afforded a role of being under the protection by male siblings, especially older brothers from issues ranging from bullies or sexual advances by womanizers.

Some studies have found that sisters display more traits indicating jealousy around their siblings than their male counterparts, brothers. The English word sister comes from Old Norse systir which itself derives from Proto-Germanic *swestēr, both of which have the same meaning, i.e. Three sisters from the Spencer family, circa 1902.

Wolfenstein wiki anette