Grade Levels: 3-5, 6-8

NOTE TO EDUCATORS: The movie featured in this lesson plan explains the genetic origins of sex traits during fertilization. Due to the sensitivity of this topic, consider previewing the movie before showing it to the class.

This lesson plan, adaptable for grades 3-8, invites students to explore BrainPOP resources to learn about DNA and its role in determining gender. Then they’ll create a BrainPOP-style movie that answers the question of how sex is determined.

Lesson Plan Next Generation Science Standards Alignments

Students will:

  1. Brainstorm what they know about sex determination.
  2. Use a concept map to take notes on the role DNA plays in determining sex.
  3. Create a BrainPOP-style movie about sex determination.


  • Internet access for BrainPOP
  • Interactive whiteboard


DNA, Chromosomes, X Chromosome, Y Chromosome, Sperm, Egg, Haploid


Lesson Procedure:

  1. Ask students what they think determines if a baby will be a boy or girl? As they brainstorm, jot their ideas on the board or chart paper. After everyone has responded, make sure they know that DNA determines a person’s sex. Tell them that they are going to watch a movie that explains what DNA is and its role in determining sex.
  2. Show the movie Sex Determination on the whiteboard to the whole class. Turn on the closed caption option to aid in comprehension. Pause during the movie to explain points that may be complicated and/or to explain important key concepts and terms.
  3. After the movie, open Make-a-Movie on the whiteboard. Click the first letter that asks how does the 23rd pair of chromosomes determine your sex. Tell students they will make a movie that answers that question.
  4. Now have students open the Make-a-Map assignment. As they watch the movie again on their own within Make-a-Map, have them create a spider map. In the center, they should type the question from the letter: How does the 23rd set of chromosomes determine your sex?
  5. After completing their maps, instruct students to open the Make-a-Movie assignment in a second window. Have them use their notes to create their movies. Circulate as students work, answering questions as needed.
  6. When students finish their movies, divide the class into small groups. Have students share their movies with the small group.

Extension Activities:

Invite students to read the Newsela article to discover what determines a turtle’s sex.