The group say the preservation of a woman's eggs by freezing, and testing an embryo for genetic flaws by sampling a single cell, are both unproven and they suggest that any women seeking egg-freezing services should first receive comprehensive counseling.

They say even though some studies have shown that healthy babies have been born using frozen eggs or ovarian tissue, and some clinics advertise such procedures, they are far from routine.

Dr. Marc Fritz, chair of the ASRM Practice Committee says it is vital that patients completely understand any new technology and the likelihood of a successful outcome.

The ASRM says there have been some reports of women having their eggs, or in some cases ovarian tissue, frozen ahead of cancer treatment or other procedures that may destroy fertility, but at present data on the procedures is too limited for such procedures to be considered an established medical treatment.

The ASRM says there are no numbers available on how many women have tried the technique and human eggs are more fragile than human embryos, which are now commonly frozen for years before use.

The ASRM includes fertility doctors, and they also say that the growing practice of preimplantation genetic testing remains experimental.

Such testing is carried out on embryos created in lab dishes via in vitro fertilization or IVF; it involves the removal of one or more cells in order to check for genetic problems before the embryo is implanted in the mother's womb.

While it is standard for checking for genetic diseases such as cystic fibrosis, a fatal and incurable condition caused by a single mutated gene, the ASRM says there is no evidence to support the use of the procedure to improve the odds of pregnancy for an older woman, or to reduce the rate of miscarriages.

ASRM president Dr. Steven Ory says 'the use of preimplantation genetic screening for chromosomal problems may one day become an essential component of infertility therapy, but for now, available evidence does not support its effectiveness and common usage'.

The warning is opportune as many women are now delaying having children and the ASRM says egg freezing should not be offered to women who want to put off having a family purely for lifestyle reasons.

The ASRM estimates that the overall live birth rate from frozen eggs is as low as 2% per egg and warns that the figures may be even lower for women over 35 - the age at which fertility begins to decline rapidly.