Can Children "Try for Baby" in The Sims 3? No.

Children cannot use "Try for Baby" in The Sims 3. The interaction is restricted to Young Adults and Adults (and male Elders).

Why:

• Game simulates biological/reproductive maturity.
• Child life stage focuses on school, skills, friends, hobbies.
• Teen pregnancy is also disabled in base game (mods enable it).

What Kids Can Do:

• Interact with babies/toddlers (play, feed, read).
• Build relationships with family.
• Use "Ask for Help with Homework" from parents.
• Age up to Teen → Young Adult → then start a family.

Mods (PC only): InTeenimator or MCCC (Sims 4) allow teen/child pregnancy, but base game does not.