Sasak was claimed to be the spouse of T'Pel and an ancestor of Selek, who was a cousin of Sarek. This claim was made by Spock while introducing himself as "Selek" to Sarek. (TAS: "Yesteryear")
This character was only mentioned in dialogue.
While the genders of Sasak or T'Pel were not specified, two other T'Pels are known, both women.