I feel obligated to share my counter example of anecdata.
Current team of 12, 9 are young parents, other 3 in committed relationships (international team based in North America + EU).
Previous team was around 50% parents, but people went on parental leave all the time, so the number kept increasing (company based in Germany, and basically the German half of the team had all the babies, the immigrant half almost none which is interesting).
And my brother and I got our first kids the same year, so the cousin bit is also covered.
Current team of 12, 9 are young parents, other 3 in committed relationships (international team based in North America + EU).
Previous team was around 50% parents, but people went on parental leave all the time, so the number kept increasing (company based in Germany, and basically the German half of the team had all the babies, the immigrant half almost none which is interesting).
And my brother and I got our first kids the same year, so the cousin bit is also covered.