John Irving, the author of “A Prayer for Owen Meany,’’ “The Cider House Rules,’’ and “The World According to Garp,’’ among other novels, says he doesn’t have a hard time writing female characters. “No, and I don’t know why it would be or should be [difficult],’’ Irving told a Symphony Hall audience this week as part of Lesley University’s speaker series. “I think many men spend a lot more time thinking about women than they do men.’’ Irving also revealed that he creates the whole story in his head before sitting down to write it — by hand. “I have nothing against my laptop, but it’s too fast, too easy,’’ he said. “Writing by hand is more like drawing. It seems to be the right pace for me.’’