Gender. The short answer is no. There are some very high tech interventions, that are used in situations where the chance of passing a gender specific disease on to a child. However, there are a ton of old wives tales out there, about how to do this. It's not going to hurt anything to try them. Who knows? .
No. Sex used to be assigned dependent on whether you had a serviceable male phallus regardless of your genetic sex. Subsequent studies have cast doubt on this approach. In mixed gender children this decision needs to be made in a painstaking manner involving a team approach with a psychologist, endocrinologist, urologist and possibly a gynecologist.