99.9% Accurate Ultrasound Signs | How to Identify Baby Boy vs Girl

Learn the basics of fetal sex determination using the 4-nub theory and skyline sign. Dr. Maya explains how to identify early signs of gender during your ultrasound. Understanding fetal development stages can be confusing for expectant parents. This guide breaks down what to look for on your scan, focusing on the 4-nub theory and the visual markers that professionals use to assess fetal anatomy. Whether you are curious about early gender prediction or simply want to understand the biological processes occurring in the womb, this overview provides clear, educational insights. Dr. Maya walks through the visual indicators like the skyline sign to help you better interpret your ultrasound images. We also cover the physiological timeline of scrotum formation, offering a clearer picture of how these developmental milestones appear on screen. By learning these specific markers, you can approach your next appointment with a better understanding of what is actually visible during early pregnancy. Subscribe for weekly pregnancy and development breakdowns, and comment below if you have questions about your own ultrasound experience. The truth is probably NOT what you've seen on TikTok, Pinterest, or mommy blogs. In this video, Dr. Maya Lin breaks down the real ultrasound signs sonographers use to identify baby boy vs. baby girl, including the Hamburger Sign, Turtle Sign, Nub Theory, genital tubercle angle, fetal position, and the actual accuracy of ultrasound at every stage of pregnancy. Most parents hear, "It's a boy!" or "It's a girl!" during the 20-week anatomy scan — but very few understand how that determination is actually made or why ultrasound is 95–99% accurate, while 99.9% accuracy comes from genetic testing (NIPT). This video explains the peer-reviewed science behind ultrasound sex determination with no myths, no heart-rate theories, no belly-shape predictions, and no Chinese gender chart claims — just real anatomy, real research, and real clinical evidence. 👉