Billionaire Bill Gates conduct another “ask me anything” session on the popular site Reddit yesterday, and revealed numerous personal opinions — including the belief that rich people who seek immortality are “egocentric” when life-threatening diseases ravage the developing world.

He said that it “seems pretty egocentric while we still have malaria and TB [tuberculosis] for rich people to fund things so they can live longer” during the session when asked about immortality research, according to a Mirror report.

Google has been experimenting with “life extension” and is working with a company called Calico on the issue, although Gates did not mention that project by name.

Many of Gates charitable efforts focus on helping millions of people in poorer nations live longer through fighting malaria and investing in research into a way to draw clean water from excrement.

Calico has a research center in San Francisco that cost $1.5 billion and is aimed at extending the lives of people with age-related diseases. There are several other research projects aimed at that goal as well.

However, Gates’ answers continued to hone in on helping developing nations with their problems, particularly with regards to sewage since it costs money to process and it ends up in the slums of poor countries.

He said he was challenging engineers to find a way to process sewage so that it could be “covered by the energy and water (clean water) that it outputs.” He said progress has been made on that front.

Gates has conducted three AMAs on Reddit, and he answered many questions related to his charitable work as well as relatively silly and inane questions. He revealed that he feels stupid for not knowing any foreign language, noting that Facebook’s Mark Zuckerberg once hosted a session in Beijing speaking entirely in Mandarin.

He also noted that he was “pretty basic” when it comes to clothes and food despite his massive fortune. His one “big splurge” was having a plane to fly around in, he said.