It is not possible to determine the gender of a baby as early as 4 or 5 weeks into pregnancy. The earliest that most doctors can accurately determine the gender is around 16-20 weeks, during an ultrasound scan. At this stage, the genitals are developed enough to be visible on the scan. However, it's important to note that there can still be some uncertainty in determining the gender even at this stage, and it's not always guaranteed to be accurate. Some parents may choose to undergo non-invasive prenatal testing (NIPT) or other genetic tests for more accurate results, but these tests are usually done later in pregnancy, around 10-12 weeks. It's always best to consult with your healthcare provider for more information and guidance on determining the gender of your baby.