What it is
A couple who have finished their IVF journey and still hold vitrified embryos may, rather than discard them or give them to research, entrust them to another couple. The child then has no genetic link to either parent — the only technique where that is so, and what brings it close to adoption.
Who it is for
Infertility on both sides, repeated failure with donor sperm and donor eggs, risk of transmission from both parents, or a deliberate choice of this route to parenthood.
The procedure
It is heavier administratively than medically. The donating couple must consent in writing, often after a reflection period, and may withdraw until transfer. The receiving couple go through interviews and, in several countries, a court authorisation. Delays run to months, sometimes years.
Scarcity is the real obstacle: few couples take the step, and many, after years of hesitation, prefer disposal to the idea of a genetically related child raised elsewhere. That decision belongs to the donors and deserves respect.
For the recipient
It is a frozen embryo transfer: oestrogen then progesterone to prepare the lining, a check scan, then a painless transfer lasting minutes. The pregnancy rate depends on the age of the woman whose egg it was at collection, and on embryo quality.
Telling the child
The guidance converges: early, plainly, in words a child can hold. Follow-up studies of donor-conceived families show that what weighs is not the information itself but discovering it late, and from someone else.