Last I checked, parents spend just as much raising and educating boys.
Citation? Because here's one that shows that parents spend more on girls than they do on boys
If you can't get past the paywall here is the relevant section:
"To capture the effect of children’s gender on spending, we compare households with only male children to those with only female children. Table 4 shows changes in the influence of children’s gender on spending. In the early 1970s, parents in households with only male children spent significantly more than parents in households with only female children, with a gap of roughly $200 in spending. Nearly all additional spending occurred because parents with only male children spent more on education. In the 1980s and 1990s, overall spending equalized, although there were still differences in the target of parental expenditures. In the early 1980s, households with only female children spent significantly more on children’s accessories; in the 1990s, households with only female children spent significantly more on day care.
By the 2000s, however, these data show a reversal: households with only female children spent more than households with only male children. Indeed, there were significant differences in spending on goods, education, and babysitting, and the overall difference was significant. To check whether differences in spending were caused by differences on other characteristics related to spending, such as household income or education, we used regression analyses (presented in Online Resource 2), which confirm that other household characteristics cannot account for these differences.
As we expected, our results show that parents spent more on male children in the early 1970s. We also find equalization in the pattern of parental investment in the 1980s and 1990s. An unexpected result, however, is that in the 2000s, households with only female children spent more than those with only male children. Whether this pattern will persist remains uncertain, but it merits further investigation."