There is a minority of infertile couples for whom egg donation offers their only hope of parenthood. These are couples whose fertility problems usually lie within the ovaries, where for various reasons - biological or just age - the quality and number of eggs suitable for fertilisation is simply not sufficient. An egg supplied by a donor, usually available in frozen form from an egg bank, can provide that essential ingredient which nature is unable to do. Today, as official data from the UK’s regulator show, egg donation is one of the most successful fertility treatments available, particularly in women of an older maternal age.

There is, of course, one assumed downside to egg donation, and one reason why so many heterosexual couples seem not immediately so keen, and that is that any resulting baby will not share the genetic inheritance of both parents: although 50% of the baby’s genes will be derived from its father (through insemination or in vitro fertilisation) 50% of the baby’s genes will still be from the donor - and to some couples that can be difficult to accept. However, recent research has shown that the development of the baby is still significantly influenced by the uterine environment in which it grows.

As the techniques of treating infertility have expanded - even to many couples and individuals who are not biologically infertile - so the definition of ‘infertility’ has changed, now more broadly interpreted as applicable to anyone unable to achieve a successful pregnancy because of their reproductive history or age.

The treatment of same-sex female couples has become an important service in reproductive medicine. UK figures show that insemination treatments increased by 17% between 2019 and 2021, and IVF treatments by 33%, with around 4000 same-sex couples treated in 2021. Yet, since they need donor sperm for egg fertilisation, these couples must also navigate potentially complex genetic connections in their family. For most couples treated by egg and sperm donation this is not a problem, and research shows that child development is similar in families that have used egg or sperm donation, compared to standard IVF. However, the treatment options for same-sex female couples now include a technique to bring the two partners even closer together in their pregnancy and birth - in a procedure now known as shared motherhood.

The technique of shared motherhood - sometimes termed ‘reciprocal IVF’ - has been largely established and popularised by our team at London Women’s Clinic, where we reported ‘high delivery rates’ from treatments in 121 same-sex couples we treated, published in a 2018 study featured in Sociology. The procedure, has one partner providing the egg through IVF, which, after fertilisation with donor sperm, is transferred to the other partner to carry in pregnancy. This means that one partner is the genetic mother, and the other partner is the gestational mother, allowing same-sex female couples to ‘share’ biological parenthood for the first time. And now, new joint research between London Women’s Clinic and Dr Susie Bower-Brown, Kate Shaw and Professor Susan Golombok suggests that reciprocal IVF offers a fulfilling route to parenthood, as it allows two-mother families to feel less ‘biological inequality’ in their mother-child connections. The research shows that mothers found it special to share the journey to parenthood together, and that reciprocal IVF helped both mothers feel connected to each other and their baby.

The study entitled ‘Biogenetic Kinship in Families Formed via Reciprocal IVF: ‘It Was [My Partner]’s Egg . . . But My Blood Flowed through Her’ published in Sociology drew upon interviews with 14 two-mother families who had conceived via reciprocal IVF. The study reported that mothers took an active and strategic approach to understanding and creating closeness and connection within their family. This suggests that attitudes to genetic inheritance in families - particularly in families conceived by assisted reproduction - are complex.

Dr Susie Bower-Brown who led the study found that the “mothers understanding of closeness was not easily explained by genetics, gestation, blood ties, or traditional understandings of ‘family’. Instead, mothers understood closeness in a number of different ways, for example, some gestational mothers felt that pregnancy, breastfeeding and birth built close mother-child bonds”. Some genetic mothers felt that their genetic connection with their baby helped them feel secure in their relationship. For others, the gestational/genetic relationship was less important to them, and for many mothers, their biological connection between less important as their child grew up, as they formed strong relationships through the effort they put into parenting and the time spent with their child. What also seems clear from other studies - notably from the Centre for Family Research in Cambridge - is that there are no differences in parent–child relationship quality between gestational and genetic mothers in shared motherhood IVF families. And that is more good news for the couples now looking at shared motherhood to make their families.

You can learn more about using donor eggs and options for same-sex female couples on the London Women's Clinic website.