Men can be single for as long as they want and do not usually experience as harsh of criticism if that's the kind of life they want to live. At the very least, they can live a lot longer than a woman can without the harshness around them telling them they have to be married at a certain age.
No one should have to defend their singlehood, though I'm choosing to now:
Rated: PG-13 (references to sex and relationships)
Not That I Should Have to Explain Myself, But...(Entry about feeling self-conscious about being single and with no kids at age 39, but then defending some of the reasons why.)