Adopting embryos

I have been listening to a friend talk about frozen embryos which will not be used by couples having IVF. Apparently, in Victoria, these embryos can be offered to other couples for adoption. In NSW this doesn't usually happen, so unused embryos are often destroyed.

It seems strange that it is preferable to kill an embryo rather than allow it to be adopted by someone who longs for a baby. Adoption is so out of favour because of the complications it can bring for children and biological parents. It has now become preferable to be killed rather than adopted. What is going on?