1 and Leitern have different sources and processing methods.
2. Fresh mesoembryos come from fresh embryos, while aged mesoembryos come from aged embryos.
3. Fresh mesoembryos can be directly used for transplantation after treatment, while aged mesoembryos need special treatment before they can be used.
4. Embryo transfer is an advanced reproductive technology, which can help infertile patients realize their fertility wishes.