A brother is a man or boy who shares one or more parents with another; a male sibling. The female counterpart is a sister. Although the term typically refers to a familial relationship, it is sometimes used endearingly to refer to non-familial relationships. A full brother is a first degree relative. Overview
The term brother comes from the Proto-Indo-European *bʰréh₂tēr, which becomes Latin frater, of the same meaning. Sibling warmth or affection between male siblings has been correlated to some more negative effects. In pairs of brothers, higher sibling warmth is related to more risk taking behaviour, although risk taking behaviour is not related to sibling warmth in any other type of sibling pair. The cause of this phenomenon in which sibling warmth is only correlated with risk taking behaviours in brother pairs still is unclear. This finding does, however, suggest that although sibling conflict is a risk factor for risk taking behaviour, sibling warmth does not serve as a protective factor. Some studies suggest that girls having an older brother delays the onset of menarche by roughly one year. Research also suggests that the likelihood of being gay increases with the more older brothers a man has. Some analyzers have suggested that a mans attractiveness to a heterosexual woman may increase with the more he resembles her brother, while his unattractiveness may increase the more his likeness diverges from her brother.
Yaz may refer to:

People
Yazmith Bataz (born 1972), Mexican sprinter
Yaz Mubarakai (born 1975), Australian politician
Carl Yastrzemski (born 1939), American Hall-of-Fame baseball player
Mike Yastrzemski (born 1990), American professional baseball player, grandson of Carl

Other uses
Yaz culture, an early Iron Age culture of Bactria and Margiana, c. 1500-1100 BC
Yaz-class river patrol craft, Russian Coast Guard vessels
YAZ, IATA code for Tofino Airport in Tofino, British Columbia, Canada
yaz, ISO 639-3 code for the Yakö language, spoken by the Yakö people of Nigeria
Yaz (band) or  Yazoo, an English synth-pop band
Yaz Pistachio, a female character from the comic strip Bloom County
Yaz (drug), a brand name for a birth control pill containing drospirenone that may also be used for other indications
YAZ, a programmer toolkit for development of Z39.50 clients and servers

See also
Yazz (born 1960), pseudonym used by English singer Yasmin Evans
Yazz The Greatest, a stage name of American actor and rapper Bryshere Y. Gray