Private equity firms and public pension funds have long had a symbiotic relationship: The funds supply the firms with billions of dollars to invest, and the firms deliver double-digit returns that help the funds support retired public servants.

Now, pension leaders are showing a new willingness to confront private equity over the human impact of its investments.

Minnesota’s pension plan temporarily halted investments in one of Toys “R” Us’s former private equity owners, Kohlberg Kravis Roberts, after hearing that 30,000 workers laid off amid the retailer’s bankruptcy had been denied severance.

A top Oregon pension official criticized the private equity firm TPG for what he said was its serious lack of diversity, specifically citing a disparaging remark that one of the firm’s founders had made about women.