.... this isn't page 2 of a thread. That's an opening post. OK... :/
Anyway, the assertion of genuineness isn't correct in either direction; lots of genuine marriages don't have children (eg by choice, same sex couples, if one party or both are sterile), and you can easily have a child without having a genuine marriage (otherwise would be an easy fraud of wham, bam, thank you ma'am, see you in 9 months for the PR application).
Also, a couple in a genuine relationship can have children who wouldn't meet a DNA test; eg, same sex couples, adoptions (by choice, or because of inability to have children), etc.
So - no. If you're planning on popping out a child on the assumption it will bolster a fraudulent application, you're in for a shock.