Part of the limitation is due to the fact that a high percentage of embryos are genetically abnormal naturally, and "embryo glue" won't overcome that.
Inxalenye yokunyineka ibangelwa kukuba inani eliphezulu lephesenti lezihluma zembewu zinengxaki yemfuza ngokwendalo yazo yaye "iglu yezihluma zembewu" ayinakuyoyisa loo ngxaki.