Identifying multiple births can be very helpful. Family Historian can help you find and mark them.
The following Expressions are composed from two technical features: Data References and Functions; they also often involve Operators to compare values. can be used in a Querying is a very powerful feature that allows you to specify and save criteria for identifying a set of records of a given record type. to spot multiple births (note it will only find matching When an Event happened, or an Attrribute was true. so if you have 2 children with just a year) it will mark them as twins.
(%INDI.BIRT.DATE% = Field(NextSib(%INDI%),'INDI.BIRT.DATE')
(%INDI.BIRT.DATE% = Field(PrevSib(%INDI%),'INDI.BIRT.DATE')
You can then use the results to set a Flag for future use, or if you prefer, simply use the expression directly in a diagram to condition an icon or other box Events are things that happened to an Individual and Attributes are things that described them..