%0 Journal Article
%T Influence of age gap and parents¡ä ethnicity on the sex of the first born child
%A Robson Marcelo Rossi
%A Valter Augusto della Rosa
%A Enrico Colosimo
%J Revista de Biologia e Ci¨ºncias da Terra
%D 2003
%I Universidade Federal do Amap¨¢
%X The influence of parents' age gap and their ethnicity in the determination of the sex of the first born child is provided. A descriptive analysis was undertaken and ¦Ö2 test, association measures and logistic regression were applied to verify the relationship between variables. The chance that a male first child is born from a mother one to ten years older than the father is twice the chance of parents whose age gap ranges between 0 and 5 years, the father being the older. Further, the chance of a male first child born from an ethnically white male parent is approximately five times higher than that of an ethnically yellow one.
%K Ethnicity
%K age
%K Odds Ratio
%K sex
%U http://www.uepb.edu.br/eduep/rbct/sumarios/pdf/influence.pdf