People have tried to predict the sex of their offspring. 2000 years ago, Hippocrates stated that female fetuses give the mother a pale face, whereas a mother carrying a male fetus has a healthier tone to her skin. Despite efforts to find reliable indications during pregnancy to determine the gender of the offspring, none have been found.
Is there a link between hyperemesis gravidarum (HG) and the sex of the baby? 
(HG) – severe nausea and vomiting during first trimester is associated with raised concentration of human chorionic gonadotropin (hCG). A
female predominance among the offspring of mothers with HG has been reported. However, the association between female fetuses and severity of HG remains uncertain. Female fetuses were also significantly associated with severe ketonuria and high urea
Reference:Askling J, Erlandsson G, Kaijser M, Sickness in pregnancy and sex of child, The Lancet, 354, Dec 11, 1999
Montes et al, Hyperemesis Gravidarum and the sex of the offspring, Epidemiology. 12(1):123-124, January 2001
PC Tan, R Jacob, KF Quek, The fetal sex ration and metabolic, biochemical, haematological and clinical indicators of severity of hyperemesis gravidarum, BJOG, 113(6), 733-737