The Federal Circuit recently held an asserted patent was not entitled to its priority date because the priority application lacked written description support for the asserted claims. In so doing, the court explained that broad disclosures that do not provide reasonably specific support for narrower claims do not meet the written description requirement. The court also considered whether the inventor’s testimony showed they possessed the full scope of the claimed genus at the priority date or whether it was more likely the inventors first became aware of the claimed embodiments from public disclosures of the accused product.