This paper presents an evaluation of and offers recommendations for assays to detect chemically induced aneuploidy in mammalian female germ cells. 72 papers on female germ cell aneuploidy, published from 1970 to 1984, were reviewed. 28 papers were selected for critical evaluation; the other 44 papers were rejected according to pre-established criteria. Salient points emerging from the information reviewed allow an assessment of the current status of mammalian female germ cell tests for aneuploidy. The majority of data have been obtained by analyzing metaphase II mouse oocyte chromosomes following superovulation. Various classes of chemicals were administered usually around the time of ovulation. Dose-response relationships have not been obtained for the majority of chemicals evaluated. The method of data reporting and analysis usually was not conducive to comparisons among different studies. Few of the 16 chemicals studied can be regarded as negative for their ability to induce aneuploidy, whereas an even smaller number should be considered as positive. Certainly, a need exists to identify the chemicals and the dosages that could increase the incidence of aneuploidy in mammalian female germ cells. Obtaining such data definitely is feasible in cytogenetic laboratories. However, the mammalian female germ cell aneuploid assay should not be perceived as a rapid, inexpensive, routine procedure. The assay is capable of detecting aneuploidy following anaphase I when metaphase II oocytes are studied and following anaphases I and II when first-cleavage zygotes are studied.