Delayed Menstruation Regularity – DES Granddaughters participating in the long-running National Cancer Institute DES Follow-up Study reported menstruation starting at about the same age as unexposed women. But it took longer for DES Granddaughters to achieve regular menstrual periods, meaning a period is predictable within five days. This small study also hints at the possibility that infertility may be more frequent in DES Granddaughters, but the researchers are quick to point out that further studies are needed.

Hypospadias – A study done by the Netherlands Cancer Institute indicates that male children of DES Daughters may be at greater risk for this birth defect than unexposed individuals. Hypospadias is a condition where the urethral opening on the penis is in the wrong place, emerging somewhere down the penis shaft instead of at the tip. In many cases hypospadias can be corrected with surgery. Of note is that other studies have failed to replicate this finding.

Tumor Growth – Animal studies indicate a higher rate of tumor growth in DES Grandson and Granddaughter mice than in unexposed animals. But researchers caution that more studies are needed to prove conclusively that this finding in DES-exposed mice also occurs in humans.