Will i be able to find out what im having at 4 months?

Yes: I am assuming you are referring to pregnancy and determining the sex of the baby? Yes, a good ultrasonographer should be able to ascertain the sex of the baby at this time. However, remember that the indication for the ultrasound is for diagnosis of the problems of the pregnancy and to date the pregnancy and determining the sex is not the purpose. I would shudder at # done and $ spent fot this.

In theory, yes.: The parts are there but whether you could see the proper parts on ultrasound would depend on a number of factors such as having an accurate due date, baby's position in the uterus, and the sonographer's skill. There are ways to find out the genotype of the baby (which would say for sure what sex it is) but they are invasive and carry a risk of spontaneous abortion, so they are not done routinely.