This is actually a really weird claim. We know now thanks to Kepler that many stars have planets just like our Sun does, but so far we've only been able to see large gaseous planets and a few rocky ones that can be as large as 1.5x Earth.

25% sounds way too high. We have not even found many stars like our own with rocky Earths like our own yet. I am certain we will eventually find them, but I think the number of rocky planets with oxygen atmosphere and liquid water is going to be under 1%.

Life is most likely rare but abundant- 1% of 100 billion is a butt-ton of Earths