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The majority of U.S. nonmarital births today are to cohabiting couples. This study focuses on transitions to cohabitation or marriage among pregnant unmarried women during the period between conception and birth. Results using the newly-released 2006–2010 National Survey of Family Growth show that nonmarital pregnancy is a significant precursor to cohabitation before childbirth (18 percent), exceeding transitions to marriage (5 percent) by factor of over three. For pregnant women, the boundaries between singlehood, cohabitation, and marriage are highly fluid. The results also reveal substantial variation in post-conception cohabiting and marital unions; e.g., disproportionately low percentages of black single and cohabiting women transitioned into marriage, even when conventional social and economic risk factors are controlled. The multivariate analyses also point to persistent class differences in patterns of family formation, including patterns of cohabitation and marriage following conception. Poorly educated women, in particular, are much more likely to become pregnant as singles living alone or as partners in cohabiting unions. But compared with college-educated women, pregnancies are less likely to lead to either cohabitation or marriage. This paper highlights the conceptual and technical challenges involved in making unambiguous interpretations of nonmarital fertility during a period of rising nonmarital cohabitation.

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This paper evaluates comparative patterns of fertility in new Hispanic destinations and established gateways using pooled cross-sectional data from the 2005–2009 microdata files of the American Community Survey. Changing Hispanic fertility provides a useful indicator of cultural incorporation. Analyses show that high fertility among Hispanics has been driven in part by the Mexican-origin and other new immigrant populations (e.g., noncitizens, those with poor English language skills, etc.). However, high fertility rates among Hispanics – and Mexican-origin Hispanics in particular – cannot be explained entirely by socio-demographic characteristics that place them at higher risk of fertility. For 2005–2009, Hispanic fertility rates were 48 percent higher than fertility among whites; they were roughly 25 percent higher after accounting for differences in key social characteristics, such as age, nativity, county of origin, and education. Contrary to most previous findings of spatial assimilation among in-migrants, fertility rates among Hispanics in new destinations exceeded fertility in established gateways by 18 percent. In the multivariate analyses, Hispanics in new destinations were roughly 10 percent more likely to have had a child in the past year than those living in established gateways. Results are consistent with sub-cultural explanations of Hispanic fertility and raise new questions about the spatial patterning of assimilation and the formation of ethnic enclaves outside traditional settlement areas.

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The potential clinical utility of genetic markers associated with response to fluoropyrimidine treatment in colorectal cancer patients remains controversial despite extensive study. Our aim was to test the clinical validity of both novel and previously identified markers of adverse events in a broad clinical setting. We have conducted an observational pharmacogenetic study of early adverse events in a cohort study of 254 colorectal cancer patients treated with 5-fluorouracil or capecitabine. Sixteen variants of nine key folate (pharmacodynamic) and drug metabolising (pharmacokinetic) enzymes have been analysed as individual markers and/or signatures of markers. We found a significant association between TYMP S471L (rs11479) and early dose modifications and/or severe adverse events (adjusted OR = 2.02 [1.03; 4.00], p = 0.042, adjusted OR = 2.70 [1.23; 5.92], p = 0.01 respectively). There was also a significant association between these phenotypes and a signature of DPYD mutations (Adjusted OR = 3.96 [1.17; 13.33], p = 0.03, adjusted OR = 6.76 [1.99; 22.96], p = 0.002 respectively). We did not identify any significant associations between the individual candidate pharmacodynamic markers and toxicity. If a predictive test for early adverse events analysed the TYMP and DPYD variants as a signature, the sensitivity would be 45.5 %, with a positive predictive value of just 33.9 % and thus poor clinical validity. Most studies to date have been under-powered to consider multiple pharmacokinetic and pharmacodynamic variants simultaneously but this and similar individualised data sets could be pooled in meta-analyses to resolve uncertainties about the potential clinical utility of these markers.

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