You can start to determine the gender of a baby during pregnancy as early as around 10 to 11 weeks through genetic blood tests like Non-Invasive Prenatal Testing (NIPT), which analyzes the baby’s DNA in the mother's bloodstream. This is the earliest reliable method. For ultrasound, the earliest gender determination can be attempted using the “nub theory” as early as 11 weeks, but the accuracy improves with time. By around 14 to 16 weeks, it becomes more visible via ultrasound, but doctors usually recommend waiting until the anatomy scan at about 18 to 22 weeks for the most reliable determination. The highest accuracy is typically reached at this 20-week scan, although visibility depends on factors like the baby’s position and the skill of the technician. In summary:
- NIPT blood test: from about 10-11 weeks
- Ultrasound gender guess: possible from about 11-14 weeks but less certain
- Most reliable ultrasound gender determination: 18-22 weeks, usually around 20 weeks
Absolute confirmation of the baby's gender comes at birth, as ultrasounds and tests carry a small chance of error.
