Establishes the "Defining SEX Act"

Healthcare

Passed Legislature

This bill passed both chambers and reached final enrollment, even if later executive action is not shown here.

Sponsor: Loy, Cathy Jo (163)
Last action: 2026-05-15
Official status: 05/15/2026 - Referred: Emerging Issues(H)
Effective date: 2026-08-28

Plain English Breakdown

The bill summary and digest do not provide additional details beyond what is in the official text.

Defining SEX Act

This act establishes a law that defines 'sex' as biological male or female based on reproductive systems and clarifies the use of terms like 'gender' in existing state laws.

What This Bill Does

Defines 'female' as someone who has, had, will have, or would have (except for certain medical conditions) a reproductive system that produces, transports, and uses eggs for fertilization.
Defines 'male' as someone who has, had, will have, or would have (except for certain medical conditions) a reproductive system that produces, transports, and uses sperm for fertilization.
States that in existing state laws, the term 'gender', when used alone, refers to biological sex unless explicitly defined otherwise.
Clarifies that 'gender identity' if used in state law is not considered a synonym or substitute for 'sex'.
Ensures individuals with disorders of sex development have legal protections under federal disability laws.

Who It Names or Affects

People who are affected by Missouri's state laws and administrative rules.
Individuals born with medically verifiable diagnoses of disorders or differences in sex development.

Terms To Know

Disorders or Differences in Sex Development: Medical conditions that affect the typical development of reproductive systems.
Gender Identity: A person's internal sense of their gender, which may not align with their biological sex.

Limits and Unknowns

The act does not define or regulate how 'gender' should be used when it modifies other words in existing laws.
It is unclear if the act will change how state agencies interpret and apply existing laws involving gender terms.
The impact on individuals with intersex conditions beyond legal protections under disability acts remains unspecified.

Bill History

2026-05-15 Missouri House of Representatives and Missouri Senate
Referred: Emerging Issues(H)
2026-01-08 Missouri House of Representatives and Missouri Senate
Read Second Time (H)
2026-01-07 Missouri House of Representatives and Missouri Senate
Read First Time (H)
2025-12-01 Missouri House of Representatives and Missouri Senate
Prefiled (H)

Official Summary Text

Establishes the "Defining SEX Act"

Current Bill Text

Read the full stored bill text

SECOND REGULAR SESSION
HOUSE BILL NO. 1779
103RD GENERAL ASSEMBL Y
INTRODUCED BY REPRESENT A TIVE LOY .
3990H.01I JOSEPH ENGLER, Chief Clerk
AN ACT
T o amend chapter 213, RSMo, by adding thereto one new section relating to the biological
definition of male and female.
Be it enacted by the General Assembly of the state of Missouri, as follows:
Section A. Chapter 213, RSMo, is amended by adding thereto one new section, to be
2 known as section 213.014, to read as follows:
213.014. 1. The pr ovisions of this section shall be known and may be cited as the
2 "Defining SEX Act".
3 2. The following terms shall mean:
4 (1) "Female", an individual who has, had, will have, or would have, but for a
5 developmental or genetic anomaly or historical accident, the repr oductive system that at
6 some point pr oduces, transports, and utilizes eggs for fertilization;
7 (2) "Male", an individual who has, had, will have, or would have, but for a
8 developmental or genetic anomaly or historical accident, the repr oductive system that at
9 some point pr oduces, transports, and utilizes sperm for fertilization;
10 (3) "Sex", an individual's biological sex, either male or female.
11 3. Unless context or explicit definition indicates otherwise, "gender", when used
12 alone, rather than with or as an adjective modifying other words, in preexi sting state
13 law , administrative rules, or guidelines to refer to males, females, or the natural
14 differ ences between males and females, shall be consider ed a synonym for "sex".
15 4. "Gender", when used alone, rather than with or as an adjective modifying
16 other words, in preexi sting state law , administrative rules, or guidelines to r efer to
17 males, females, or the natural differ ences between males and females, shall not be
EXPLANA TION — Matter enclosed in bold-faced brackets [thus] in the above bill is not enacted and is
intended to be omitted from the law . Matter in bold-face type in the above bill is proposed language.
18 consider ed a synonym or shorthand expr ession for "gender identity (an internal sense of
19 gender)", "experienced gender", "gender expr ession", or "gender role" .
20 5. "Gender identity", if used in state law , administrative rules, or guidelines,
21 shall not be consider ed a synonym or substitute for "sex" or "gender".
22 6. An individual born with a medically verifiable diagnosis of a disorder or
23 differ ence in sex development shall enjoy the releva nt legal prot ections and
2 4 accommodations afforded under the federal Americans with Disabilities Act.
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HB 1779 2