Fertility companies are paying egg donors high fees that often exceed guidelines, especially for donors from top colleges and with certain appearances and ethnicities, a new study finds.

The upshot: Parents with infertility problems are willing to pay up to $50,000 for a human egg they hope will produce a smart, attractive child.

The first baby conceived through egg donation was born in 1983. Since then, the practice, which involves transferring fertilized eggs from a donor into a woman's body, has grown dramatically. The rise has been seen particularly among women with ovarian failure, women over 40, and gay men who want to have children through surrogate pregnancy.

While there are few government regulations controlling the use of this technology, the American Society for Reproductive Medicine (ASRM), a professional organization, has issued guidelines. The ASRM ethics committee recommends limits on the amount of money egg donors should be paid, saying "sums of $5,000 or more require justification and sums above $10,000 are not appropriate."