Second TrimesterWeek 27 of 40

Baby Gender Prediction at 27 Weeks

At 27 weeks, your baby's gender is definitively identifiable on any good quality ultrasound. You're in the second trimester and the external genitalia are fully formed — direct observation gives the highest possible accuracy.

Your Baby at 27 Weeks

  • Baby measures approximately 240mm — about the size of a cabbage
  • All major organs are developed and functioning at 27 weeks
  • Baby is gaining weight and building fat deposits steadily

Gender Prediction Methods at 27 Weeks

Nub Theory

✓ Available~90%+ (direct observation)

Nub theory is no longer relevant at 27 weeks — the genitalia are directly observable and provide near-definitive results from a good quality scan.

Skull Theory

✓ Available~80-85%

Skull theory can still be applied at 27 weeks as a supplementary method with around 80-85% accuracy.

Chinese Gender Calendar

✓ Available~50-70% (varies by study)

The Chinese Gender Calendar is always available for a quick cultural check — though at this stage your ultrasound result is almost certainly confirmed.

AI Ultrasound Analysis

✓ Available~93-99%

AI analysis at 27 weeks achieves ~95-99% accuracy. The fully-formed external genitalia provide clear, unambiguous markers for our model.

Get Your AI Gender Prediction

Upload your 27-week scan — our AI will confirm your baby's gender with near-complete accuracy at this stage.

Upload Your 27-Week Scan →

Frequently Asked Questions

Can you tell the gender of a baby at 27 weeks?

Absolutely — at 27 weeks, gender determination is near-certain from a clear ultrasound. Both your sonographer and our AI can give you a highly reliable answer.

How accurate is gender prediction at 27 weeks?

Around 95-99% accuracy from direct observation and AI analysis at 27 weeks. This is as definitive as it gets without a genetic test.

What does a boy/girl look like on an ultrasound at 27 weeks?

At 27 weeks, male and female genitalia are fully formed and clearly visible. Boys show a clearly defined penis and scrotum; girls show the labia with the characteristic three-line appearance.