Fertility treatments (for the purpose of this information page) means a procedure where an egg is fertilized outside the 'mothers' body.
In the UK the only form of fertility treatment that is likely to be available to lesbians is in vitro fertilization with the mother's ovary. The difficulties in obtaining this service are similar to that of obtaining donor insemination from clinics, the main difference being that the cost of IVF is much higher.
The legal implications are similar to insemination. When a known donor is used they have the same rights and responsibilities of an unmarried father.