As a new member of the forum and a new father, I wanted to detail my experience with immigration and procuring my son's birth certificate.
1) My marriage was registered in Bengaluru and the marriage certificate had to be attested by the MEA when my wife wanted to move to Zurich on a dependent visa. All civil documents (marriage certificates, birth certificates, notarized affidavits) *have* to be apostilled by the MEA. This is due to India and Switzerland both being signatories of the Hague convention of 1961. Over and above this, the Swiss immigration authorities (actually the Migration Office of respective Kanton) retain the power to authorize the Swiss Embassy in India to re-verify the apostilled document. This cost me around 900 CHF and took 2 months to complete. I contacted the Indian Embassy in Berne about this, but they bluntly told me that this is not a matter of their concern. The Swiss consulate in Mumbai hired a private firm to visit my house and my wife's house to verify the authenticity of the marriage. This was all in Oct-Dec 2012.
2) For the birth certificate, I contacted the Zivilstandsamt in Zurich roughly 5 months before the baby was born. The parents' birth certificate (the birth extract from the actual registry of birth from the local municipality, to be precise) and the marriage certificate, all apostilled by the MEA is a *must*. If you do not have a birth certificate, you need to get it done one way or another. Both of us had our birth certificate issued at the time of birth itself, so getting he extract and the apostille was only a matter of time and money. I used the service from www.yourmaninindia.com
for this. They were very professional and quick on the task. The service charges are rather high for document procurement from smaller towns, but they get the job done. For the apostilled birth certificates, *no* further verification was done by the Swiss Embassy. We received a Familienausweis within 2 weeks of submitting our apostilled birth certificates. At the time of my son's birth, we submitted this ausweis in original to the hospital alongwith the other hospital documentation. The birth certificate and the updated Familienausweis arrived in my mailbox less than a week after the birth.
My 2 cents: the verification by the Swiss Embassy will happen atleast once, if not at the time of immigration, then at the time of obtaining the birth certificate. I do not think it happens twice, because the investigation is not only to establish the validity of marriage/birth and related documents, but also of your identity. The requirements seem to be especially stringent in Zurich. Planning in advance (3-4 months) for both immigration and for the birth certificate is highly recommended.