I think more than housing prices need to come down for that to happen. We'd need young people to not be living pay-check to pay-check. To echo the other comment

I think more than housing prices need to come down for that to happen. We'd need young people to not be living pay-check to pay-check. To echo the other comment, this isn't the pre-1900's where children were mostly self-sustaining free labor. In the UK, the average savings (net financial wealth) at 25 - 29 years old is £3,800, but the typical person in that age range has -£100. The average UK savings for 30 - 34 year old's is around £14,500 of net financial wealth (savings like current and savings accounts, stocks, bonds, etc. less financial liabilities), but the median figure is just £1,000. By the time anyone is in a financially secure enough position to have children, they're at the stage where they're spending thousands in fertility treatment.