They have described the proposals as "unethical" and are seriously worried that they will put women and their babies at risk.
Members of the Italian Lower House decided that the freezing of ooctyes and sperm is acceptable but that freezing embryos - currently the most effective way to preserve surplus embryos - is not.
The number of oocytes that can be inseminated would be limited to three. But, particularly controversially, they have also decided that all embryos resulting from the insemination must be transferred to the patient at one time. This means that a woman will be put at risk of giving birth to triplets, with all the risks to mothers and babies involved.
The proposals will go before the Italian Senate within the next few months for final approval.
Speaking on the eve of the annual conference of the European Society of Human Reproduction and Embryology, ESHRE chairman Professor Hans Evers said: "We are so concerned at the implications that we discussed them today at our executive committee meeting.
"Cryopreservation of oocytes has shown promising results at one Italian centre, but is still an experimental procedure, and the limited number of procedures performed so far is insufficient to establish its safety.
"It is unethical to subject women to a procedure that is of low efficacy and the safety of which is still a concern. Any procedures like this should be undertaken only in controlled clinical trials."
He said that ESHRE was also deeply concerned that the decision may encourage other countries to pass similar laws. "In the current state of knowledge that would be disastrous for women."
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