New laws coming into force next month will allow women undergoing infertility treatment to put almost any other adult on their child's birth certificate.
The move is designed to aid lesbian couples and single women who often face obstacles when trying to access infertility treatment.
According to the Human Fertilisation and Embryology Authority's (HFEA's) website, the woman undergoing infertility treatment "can consent to any man or woman being the father or second parent as long as they are not 'within prohibited degrees of relationship in relation to each other...", for instance a brother or aunt.
A spokeswoman for the HFEA said that the new rules "will make things easier" for lesbian couples.
However, the head of Fertility Focus Professional Services has pointed out that the change could have far-reaching consequences.
Consultant gynaecologist Gedis Grudzinskas noted that the future of medicine is likely to be driven by genetics.
"To benefit from those developments a child will need to know who its genetic parents are," he explained.
"Previously one would have assumed that they are the people mentioned on the birth certificate, even if that was not always correct, but now a child can have 'social parents' and 'genetic parents' it is going to be far more complicated and difficult."
The expert warned that some children may therefore miss out on any future developments in genetics-based medicine that might have been beneficial for their health.