I don't think I've seen this on this forum, so in case anyone else is wondering how the mechanics of this works (extending my Gold status, not how babies are made
), I've copied the response I received from Flying Club Support, below. I assume this benefit extends to adoptions too, as it does with BA.
I sent in everything this morning, and a few hours later, my FC account (and also my OH's) has been 'made up' to 1,000 Tier Points. My membership year doesn't end until October, and my wife's ends in June.
NYLON
--
Thank you for your email.
Congratulations for the new addition to your family.
Due to maternity and paternity leave, Gold and Silver Flying Club members can apply for an extension to their account to retain their Gold or Silver status.
We will add the amount of tier points required to maintain the members status, enabling the member to continue at either Gold or Silver status for a further 12 months from their renewal date.
In order to process your request with regards to claiming the maternity benefit, please supply one of the following documents as proof:
a) Hospital booklet (detailing birth/pregnancy)
b) Hospital letter (detailing birth/pregnancy)
c) Copy of the infant birth certificate
When sending us the requested documentation, please include a short covering note including your Flying Club number. If you are sending scanned copies of your documents, please ensure that the attachments are in PDF format.
Thank you once again for contacting us.
Thanks and Regards
Flying Club Support

I sent in everything this morning, and a few hours later, my FC account (and also my OH's) has been 'made up' to 1,000 Tier Points. My membership year doesn't end until October, and my wife's ends in June.
NYLON
--
Thank you for your email.
Congratulations for the new addition to your family.
Due to maternity and paternity leave, Gold and Silver Flying Club members can apply for an extension to their account to retain their Gold or Silver status.
We will add the amount of tier points required to maintain the members status, enabling the member to continue at either Gold or Silver status for a further 12 months from their renewal date.
In order to process your request with regards to claiming the maternity benefit, please supply one of the following documents as proof:
a) Hospital booklet (detailing birth/pregnancy)
b) Hospital letter (detailing birth/pregnancy)
c) Copy of the infant birth certificate
When sending us the requested documentation, please include a short covering note including your Flying Club number. If you are sending scanned copies of your documents, please ensure that the attachments are in PDF format.
Thank you once again for contacting us.
Thanks and Regards
Flying Club Support