Can a man only make single sex gender babies?

A man's sperm will determine the sex of a baby, if that's what you mean. The sex of a baby is determined by the sex chromosomes, called the X and Y chromosome. Females carry two X chromosomes in their cells, and so every egg that a female produces contains one X chromosome. Males carry one X and one Y chromosome. A sperm can therefore contain either an X chromosome or a Y chromosome. If an egg is fertilized by an X-carrying sperm, the resulting fertilized egg will have two X chromosomes, and give rise to a female baby. If an egg is fertilized by a Y-carrying sperm, the resulting fertilized egg will have one X and one Y chromosome, and the baby will be male. This assumes that the eggs and the sperm are normal. There are genetic abnormalities that can result in fertilized eggs having, for example, two X and one Y chromosomes, a condition referred to as "XXY males," some of whom will develop a set of symptoms called Kleinfelter's syndrome. In general, the presence of a Y chromosome makes a person a male, irrespective of how many X chromosomes are also carried.