Montana legislation · 2025 Regular Session
Montana SB437: Revise definition of sex in Montana law
Status: Signed into law, March 25, 2026
What the bill says
An act for the codification and general revision of the laws relating to the definition for the words sex, female, male, man, woman, father, and mother when referring to a human; providing that the definition of sex refers to biological sex and not gender identity or sexual intercourse; providing that the definition of sex is limited to two types of sexes which are referred to as male and female; providing that the definitions of male, female, man, woman, father, and mother refer to biological sex and not subjective gender identity; clarifying the meaning of the term "gender"…
From the engrossed text:
AN ACT FOR THE CODIFICATION AND GENERAL REVISION OF THE LAWS RELATING TO THE DEFINITION FOR THE WORDS SEX, FEMALE, MALE, MAN, WOMAN, FATHER, AND MOTHER WHEN REFERRING TO A HUMAN; PROVIDING THAT THE DEFINITION OF SEX REFERS TO BIOLOGICAL SEX AND NOT GENDER IDENTITY OR SEXUAL INTERCOURSE; PROVIDING THAT THE DEFINITION OF SEX IS LIMITED TO TWO TYPES OF SEXES WHICH ARE REFERRED TO AS MALE AND FEMALE; PROVIDING THAT THE DEFINITIONS OF MALE, FEMALE, MAN, WOMAN, FATHER, AND MOTHER REFER TO BIOLOGICAL SEX AND NOT SUBJECTIVE GENDER IDENTITY; CLARIFYING THE MEANING OF THE TERM "GENDER"; AMENDING SECTIONS 2-18-208, 2-18-606, 7-15-4207, 7-34-2123, 10-2-403, 13-27-408, 13-35-301, 13-38-201, 13-38-203, 13-38-205, 19-2-802, 20-6-808, 20-7-1306, 20-7-1703, 20-9-327, 20-11-116, 20-25-501, 20-25-707, 22-2-306, 23-2-505, 33-1-201, 35-20-209, 39-2-912, 39-29-101, 39-71-401, 40-1-107, 40-1-311, 40-1-401, 40-5-804, 40-5-907, 40-5-1031, 40-6-701, 40-6-703, 41-3-210, 41-5-103, 42-2-204, 44-2411, 44-2-412, 45-5-625, 46-18-101, 46-19-301, 46-19-401, 49-1-102, 49-2-101, 49-3-101, 50-4-720, 50-5-105, 50-5-602, 50-11-101, 50-15-101, 50-19-103, 50-19-501, 50-60-214, 53-20-142, 53-21-121, 53-21-142, 53-24310, 53-30-312, 60-5-514, 60-5-522, 61-5-107, 72-1-103, 72-17-106, AND 90-14-104, MCA; REPEALING SECTION 1-1-201, MCA; AND PROVIDING AN IMMEDIATE EFFECTIVE DATE. WHEREAS, in human beings, there are two -- and only two -- sexes: male and female, which refer to the two body structures (phenotypes) that, in normal development, correspond to one or the other gamete -- sperm for males and ova for females; and WHEREAS, …