The earliest reliable method to find out a baby's gender is through Non- Invasive Prenatal Testing (NIPT), which can be done as early as 10 weeks into pregnancy with over 95% accuracy. Ultrasound can sometimes indicate gender starting around 12 to 14 weeks, but it is most accurate between 18 and 22 weeks when the anatomy scan is usually performed. There are also specialized blood tests and genetic testing methods used in IVF that can reveal gender even earlier, but these are more invasive or specialized. Here are some detailed points about early gender determination:

• NIPT is a blood test analyzing fetal DNA in the mother's blood and can determine gender with high accuracy by about 10 weeks of pregnancy.
• Ultrasound gender prediction can start as early as the 11th or 12th week, but accuracy improves after 14 weeks, and is highest around 18 to 22 weeks.
• At 11 to 12 weeks, ultrasound identification is about 65% successful in detecting gender, with accuracy for identified cases around 88-97%.
• The formation of genitalia starts around week 7, but clear differentiation typically appears around week 14 to 15.
• Some at-home gender prediction kits claim to offer results from about 7 weeks, but these are less regulated and less reliable.
• Genetic testing during IVF or invasive tests like chorionic villus sampling (CVS) can determine gender nearly 100% accurately early on but have associated risks.

In summary, for confident and early knowledge of gender, NIPT at 10 weeks is the earliest practical test, while ultrasound becomes more dependable from 14 weeks onwards, with the standard anatomy scan at 18-22 weeks being the gold standard for accuracy and confirmation.