No diet will determine your child's sex. Despite what you may have read or heard about high-calorie diets making you more likely to have a boy or acidic foods making you more likely to have a girl, there's no scientific proof for these claims. If there are medical reasons for wanting a boy or a girl, like a sex-linked hereditary disorder, you can talk to a fertility specialist about assisted reproductive technologies. In vitro fertilization with preimplantation genetic diagnosis (IVF-PGD) is a highly effective method of determining the sex of a fertilized embryo before implantation.