Or HaChaim on Leviticus 3:1/אור החיים על ויקרא ג׳:א׳

1 אם זכר אם נקבה, be it male or female; the repetition of the word אם between the words זכר and נקבה indicates that the Torah does not favour a male animal over a female animal when it comes to the offering of such peace-offerings.