Here's the link to the research results: http://www.ncbi.nlm.nih.gov/pubmed/18752885?dopt=Citation
Here's the link the the HER foundations Research page: http://www.helpher.org/HER-Research/
I thought the conclusion was a little hopeful. Maybe they'll figure this out one day, after all.
" CONCLUSION: There is a high prevalence of severe nausea and vomiting of pregnancy/hyperemesis gravidarum among relatives of hyperemesis gravidarum cases in this study population. Because the incidence of hyperemesis gravidarum is most commonly reported to be 0.5%, this study provides strong but preliminary evidence for a genetic component to extreme nausea and vomiting of pregnancy."