What role does FTO play in Fruchtbarkeit?

The provided knowledge context contains no information on the role of the FTO gene in fertility. The only FTO-related content is from a Q&A batch linking the rs9939609 risk allele to a slightly increased obesity risk (OR up to 2.1), with no mention of reproductive traits. In the broader literature, FTO is primarily associated with energy balance and body weight; indirect effects on fertility (e.g., via obesity-related hormonal changes) are plausible but not supported by the given sources. Direct genetic associations between FTO variants and female or male fertility (such as PCOS or sperm quality) are absent from the context. Therefore, the evidence for a specific role of FTO in fertility is classified as unclear. Consumer DNA tests that claim such links often overstate the evidence. It is not advisable to alter lifestyle or family planning decisions based solely on a single FTO SNP.