Male birth rates are influenced by the insemination of unselected spermatozoa and not by clomiphene citrate

Preconceptional sex selection: past, present, and future

Predetermination of sex in human and in farm animals is reviewed. Preconceptional sex selection has generated great interest and controversy over the years. Medical and commercial benefits outweigh the ethical issues. Technology has not yet provided a routine method for separating the X- and Y-chromosome-bearing sperm. Flow cytometry is the only technique that produces a clinically significant enrichment of X- or Y-bearing spermatozoa However, concern has been raised about the methodological implications of the flow technique because of the use of DNA stains and UV light. Some other techniques, such as gradient columns, appear to produce a slight enrichment of one type of sperm over the other, but this level of enrichment appears unlikely to affect the sex ratio at birth. It thus remains speculative whether 100% pure preparation of X or Y sperm can be obtained unless a major improvement in methodology is achieved. Fluorescence in situ hybridization (FISH) and polymerase chain reaction (PCR) are currently the methods of choice for evaluating the validity of the sex selection procedure. In view of the extraordinary pace of the technological and scientific progress, it can be expected that the clinical and commercial application of the technology of preconceptional sex selection by X and Y sperm separation will be a reality in near future.

Effects of cryopreserved semen quality and timed intrauterine insemination on pregnancy rate and gender of offspring in a donor insemination program

PURPOSE

Our purpose was to study the relationship among cryopreserved donor semen quality, pregnancy rates, and preconception sex selection after intrauterine insemination.

METHODS

We reviewed the records of the 203 women in our donor insemination program from 1987 to 1994 who became pregnant after more than one insemination cycle and had no female-factor infertility. They were categorized according to the number of cycles required for pregnancy. Semen samples from 54 donors were analyzed before freezing and after thawing. Specimens resulting in pregnancy were compared to specimens from the same donor that did not. Semen characteristics were compared to gender of the child.

RESULTS

Two hundred fifty two-women became pregnant of the 422 who were enrolled. The pregnancy rate per cycle was 13%. Semen quality was not related to pregnancy outcome or offspring gender. However, more male children (101 vs 83) were born.

CONCLUSIONS

Semen characteristics in good-quality cryopreserved donor semen do not affect pregnancy rate or offspring gender.