Reciprocal translocations involving two chromosomes frequently cause abortion of unbalanced offspring. In many cases, however, meiosis leads to a cytogenetically normal or balanced gamete with normal embryonal development. In a couple investigated because of recurrent reproductive loss, the husband had a reciprocal exchange of parts of the long arms of chromosomes 9 and 10 in the form of inverted insertions. Due to difficulties in obtaining regular homologous pairing during zygotene, this anomaly might not be compatible with cytogenetically normal or balanced offspring. The diagnosis of this translocation was possible using a previously published alkaline Giemsa G-banding technique.