Apparently on the dating/marrying scene, guys who have children and are paying child support and/or visiting their children regularly are more likely to have a new relationship than men who don't have kids or who don't pay child support and/or visit their kids.
There's a motivation for paying child support. “Get more dates if you pay!”
A study about single parents shows that Dad's relationship is helped by having kids. However, Mother's relationships are hampered. This is probably because Dads are most often the visiting parents. Having kids may be a sign to other women that the guy is willing to settle down. Apparently guys don't need/want a sign that women will settle down. (What a surprise!?) Also, being a single parent is a HUGE strain and may keep Moms too busy to meet anyone else.
It always amazes me that we have to do studies to find this stuff out. But, I guess, sometimes what we think and what actually is AREN'T the same.