Hi Anderson
These are the children showing for an Alexander and Margaret Comrie on IGI which probably relate to your couple. With the exception of the first birth in 1853 which is a submitted entry, all the rest are actual extracts, post official registration in 1855:
1. JANE RANKIN Birth: 05 JUN 1872 Kilsyth, Stirling, Scotland
2. PETER COMRIE RANKIN Birth: 10 MAY 1857 Kilsyth, Stirling, Scotland
3. CHRISTINA SMITH RANKIN Birth: 01 DEC 1860 Kilsyth, Stirling, Scotland
4. CHRISTINA SMITH RANKIN Birth: 21 APR 1865 Kilsyth, Stirling, Scotland
5. DANIEL COMRIE RANKIN Birth: 21 AUG 1869 Kilsyth, Stirling, Scotland
6. ALEXANDRA RANKIN Birth: 23 FEB 1863 Kilsyth, Stirling, Scotland
7. WILLIAM RANKIN Birth: 03 JUN 1867 Kilsyth, Stirling, Scotland
8. MARGARET MC INNES RANKIN Birth: 13 APR 1855 Kilsyth, Stirling, Scotland
9. ROBERT RANKIN Birth: 13 JUN 1853, Christening: 10 JUL 1853 Kilsyth, Stirling, Scotland
10. ALEXANDER RANKIN Birth: 29 JUL 1859 Kilsyth, Stirling, Scotland
I don't know which of their children is your line, but certainly one of the birth certs. to look at would be the 1855 cert for Margaret. The first year of official registration resulted in a wealth of info being included in BMDs that year and should hopefully give you more background on Alexander and Margaret.
Regards.
Monica