Anonymous, unidentifiable sperm and eggs may no longer be used for creating embryos in the US state of Colorado.

Gov. Jared Polis last week signed a landmark bill to make the state the first in the nation to give donor-conceived individuals the right to learn their donor’s identity when they turn 18, and access that person’s medical history before that.

The “Donor-Conceived Persons and Families of Donor-Conceived Persons Protection Act,” which takes effect Jan. 1, 2025, also caps the number of families that can use a specific donor and will require sperm and gamete banks to permanently maintain a donor’s records and regularly update their medical history. The minimum age to donate will be raised to 21.

“This is groundbreaking,” said Jody Madeira, an Indiana University law professor and expert on fertility law. “We’re really not sure what these bills should look like ideally, but we have one now.”