Because mammalian eggs are produced early in life, while sperm are created continuously, fathers are responsible for a greater share of new mutations passed down to their offspring than mothers. This slightly complicates genetics-based time-since-last-common-ancestor estimations, leading to recent results to the effect that the human-chimp split happened about twice as far back as previously thought. Adam Benton has more information, if you’re interested.
This new paper has prompted Jeffrey Tomkins, the ICR’s go-to geneticist, to publish “Chimp DNA Mutation Study–Selective Yet Surprising.” Tomkins is known for contesting the typically-cited genetic similarity figures of 94-99% and having calculated using his own method a “conservative” (i.e. maximum) figure of nearer 70%.