Is it necessary for same-sex female couples to be married to use the ROPA technique?

In order to benefit from the ROPA (Reception of Oocytes from Partner) technique, it is compulsory for same-sex female couples to be married. Otherwise, two basic principles of Spanish law regarding gamete donation would be breached, that is, donor anonymity and donor selection by a medical team, not by patients. Spanish law also provides for the civil registration of two-mother families if and when the two mothers are married.