Secondary Sex Characteristics

In AP Psychology, secondary sex characteristics are physical traits that develop during puberty (like facial hair, deepened voice, or breast development) that distinguish the sexes but are not directly involved in reproduction.

Verified for the 2027 AP Psychology examLast updated June 2026

What are Secondary Sex Characteristics?

Secondary sex characteristics are the body changes that show up during puberty but don't actually do the work of reproduction. Think facial hair and a deeper voice in males, or breast development and wider hips in females. They signal that someone is reaching sexual maturity without being the parts that make reproduction happen.

This matters because of the contrast built right into the name. Primary sex characteristics are the organs directly involved in reproduction (testes, ovaries, etc.) and are present from birth. Secondary characteristics emerge later, driven by the surge of sex hormones (androgens and estrogens) at puberty. So the line isn't "male vs. female," it's "directly used in reproduction vs. not." That distinction is the whole point on the exam.

Why Secondary Sex Characteristics matter in AP Psychology

This term lives in Topic 6.7, Gender and Sexual Orientation, inside the developmental and biological side of AP Psych. It connects the physical machinery of puberty to the bigger conversation about sex, gender, and how biology and environment interact. You'll use it to show you can tell apart what's biological and present from birth (primary characteristics) from what's hormonally triggered later in development (secondary characteristics). It's a clean, testable distinction, which is exactly why it makes good multiple-choice fodder.

How Secondary Sex Characteristics connect across the course

Puberty (Unit 6)

Puberty is the event that switches secondary sex characteristics on. The hormone surge at puberty is literally the cause, so these traits are evidence that puberty has begun.

Androgens & Estrogens (Unit 6)

These sex hormones are the chemical messengers behind the changes. Androgens drive facial hair and a deeper voice; estrogens drive breast development. No hormone surge, no secondary characteristics.

Sexual Selection & the Evolutionary Perspective (Unit 1/6)

From an evolutionary angle, secondary sex characteristics act as signals of maturity and fitness that influence mate selection. The same trait that's just "puberty" in development becomes an "advertisement" in the evolutionary story.

Gender Roles & Cultural Norms (Unit 6)

Secondary characteristics are biological, but cultures attach social meaning to them. How a society reacts to facial hair or body shape is learned, which is a clean example of biology and environment working together.

Are Secondary Sex Characteristics on the AP Psychology exam?

Expect this almost entirely in multiple choice, and almost always as a definition-by-contrast question. A classic stem asks "Which of the following is a secondary sex characteristic?" with answer choices mixing reproductive organs (primary) and puberty traits like facial hair (secondary). Another common format is the analogy stem: "Primary sex characteristic is to ______ as secondary sex characteristic is to ______." Your job is to nail the difference: directly involved in reproduction equals primary, develops at puberty but not directly reproductive equals secondary. No released FRQ uses this term verbatim, but it supports any free-response answer about puberty, hormones, or the biology of development.

Secondary Sex Characteristics vs Primary Sex Characteristics

The split is reproduction, not sex. Primary sex characteristics are the reproductive organs themselves (present from birth and directly used to reproduce). Secondary characteristics develop at puberty and distinguish the sexes but don't do reproductive work, like facial hair or breast development.

Key things to remember about Secondary Sex Characteristics

  • Secondary sex characteristics are puberty-triggered traits that distinguish the sexes but are NOT directly involved in reproduction.

  • Examples include facial hair and deepened voice in males and breast development in females.

  • The exam constantly tests the primary-versus-secondary contrast: primary = reproductive organs present from birth, secondary = puberty changes.

  • Androgens and estrogens are the hormones that cause secondary sex characteristics to appear during puberty.

  • This term sits in Topic 6.7 and links the biology of development to gender and evolutionary ideas like sexual selection.

Frequently asked questions about Secondary Sex Characteristics

What are secondary sex characteristics in AP Psychology?

They're physical traits that emerge during puberty (such as facial hair, a deeper voice, or breast development) that distinguish males and females but aren't directly involved in reproduction.

Are reproductive organs secondary sex characteristics?

No. Reproductive organs like testes and ovaries are PRIMARY sex characteristics because they're directly involved in reproduction and present from birth. Secondary characteristics show up later, at puberty.

How are secondary sex characteristics different from primary sex characteristics?

Primary characteristics are the reproductive organs themselves, used directly to reproduce, and exist from birth. Secondary characteristics develop at puberty (facial hair, breast development) and distinguish the sexes without doing reproductive work.

What causes secondary sex characteristics to develop?

The surge of sex hormones at puberty. Androgens drive male traits like facial hair and a deeper voice, while estrogens drive female traits like breast development.

Is this term actually tested on the AP Psych exam?

Yes, mostly in multiple choice. You'll see definition questions like "Which is a secondary sex characteristic?" and analogy stems comparing primary and secondary characteristics, so know the difference cold.