Professional advancement often comes through personal connections. This study analyzes how gender persistently shapes the career benefits workers enjoy from positive shocks to their network of connections. We follow mid-career academic scientists in China who compete to serve temporarily on a major scientific funding body. This role brings substantial opportunities to expand their personal networks, partly through increased interactions with senior scientists who are gatekeepers of research funding. Specifically, we estimate how service affects career advancement differentially by gender over time. For males, service is linked to a 56 percent increase in high-stakes, high-value grants awarded, a doubling of the likelihood of promotion, and more than a 20 percent increase in the likelihood of becoming a gatekeeper with whom subsequent scholars choose to network. In contrast, females experience no significant gains on any of these outcomes. This disparity appears to flow primarily through an expansion to the professional networks of male but not female scientists. Notably, the benefits of service to females and males are comparable in magnitude when female scientists have more opportunities to network with senior female scientists. These findings help explain the persistence of gender inequality in senior roles in science and other male-dominated fields.