Methodological Issues There are two strengths in this meta-analysis. First, we more clearly conceptualized the issue of parenting style. This comparison of parenting styles between IVF and NC women contributes to clinical knowledge. Second, we examined the degree of difference between the two groups regarding parenting style. This difference provides greater evidence—based insights than provided by previous descriptive studies. The moderate heterogeneity of outcomes in warm parenting behaviors revealed in this meta-analysis may result from sampling bias or from the effects of moderating Variables. Unfortunately, the source of heterogeneity could not be identified because of inconsistencies among the matched variables in these case-controlled studies. It may be that the variability arose from combining longitudinal studies with cross-sectional studies. The interstudy variability may also be the source of heterogeneity among the effect sizes (Huedo-Medina, Sanchez- Meca, Mar’1n—Martinez, & Botella, 2006). The number of characteristics that vary among the studies such as singleton or twins, birth order, child ages, child gender, number of siblings, mother’s age and socioeconomic status, times of NF cycle, and country of study may influence interstudy variability. Subgroup analyses of these characteristics are limited by the in- consistency of matched variables among the case—controlled studies. Using nonblinded interviews and self-report parenting behavior questionnaires increases the risk of bias