A federal judge has ruled that the State of Idaho cannot block transgender people from changing their listed gender of their birth certificates. 

The ruling from U.S. Magistrate Judge Candy Dale came Monday, and said that the Idaho Department of Health and Welfare violated the Equal Protection Clause of the U.S. Constitution, did not present any governmental purpose for blocking said actions, and could put transgender residents at risk by forcing them use documents for identification purposes that would disclose their status.

In her ruling, the judge stated, “A rule providing an avenue to obtain a birth certificate with a listed sex that aligns with an individual’s gender identity promotes the health, well-being, and safety of transgender people without impacting the rights of others."

This isn't a new concept, in fact, most states already allow these changes to happen.  Idaho, Ohio, Kansas, and Tennessee were the four who were prohibiting transgender people to change their listed sex on birth certificates.  That list is now down to the three remaining states.
The ruling is the result of a lawsuit brought by two transgender women from Idaho who staid that hostility and harassment occurred when presenting identification that didn't match their gender identity.
The story is getting national attention, you can find more in this article from Time.com.