“…Analyses with data only on women's children show mixed effects. On the one hand, some studies have found a clearly negative association between the risk of childbearing and the previous parity (Rindfuss and Bumpass 1977;Clarke et al 1993;Lillard, Panis, and Upchurch 1994); on the other hand, other analyses have found a non-linear negative effect of such a parity (Wineberg 1990;Jefferies, Berrington, and Diamond 2000), while still others have demonstrated no effect (Griffith, Koo, and Suchindran 1985;Diamond, Clarke, and Clarke 1995). These latter results suggest that the effect of stepchildren may not be as strong as we could expect, and that the first shared child of a second union may have a unique value which interacts with the value of those children born during the first marriage.…”