Tyl Taylor (Griffin lab) established that human embryos can be frozen and
thawed twice, if necessary, without incurring gross genetic (chromosomal)
defects.
Taylor, T.H., Patrick, J.L., Gitlin, S., Wilson, J.M., Crain, J.L. & Griffin, D.K. (2014) http://www.sciencedirect.com/science/article/pii/S147264831400131X. Reproductive BioMedicine Online, 29, 59-64.