It's when you start feeling old (not physically old) and you start to feel alone, and somehow, you have this need to create and start a new phase in your life called "family". You feel that it's time to settle down with someone for the rest of your life since you've had enough fun dating lots of people. And you wouldn't want to play this time. You're going to take it very seriously and you even consider silly things, like the one I mentioned on my post above yours.
And besides, being with someone you're attracted to in every aspect is better than being someone who you're only attracted to on a certain aspect (e.g. personality but not looks).