There is no legal requirement that you speak to a lawyer before using assisted reproduction. However, assisted reproduction can be very complicated. There can be very big consequences if something goes wrong.
If you are using a clinic for assisted reproduction, they may make you aware of some of the legal requirements. Some clinics may even require you to speak with a lawyer before they will begin a procedure. A clinic may also require that a donor or a surrogate get legal advice before they will begin a procedure.