Don't duplicate the records. If you have tblActivity, the activity gets recorded once per family. If you can have many activities related to many families then you may need a junction table where the FamilyIDfk and ActivityIDfk fields are located as foreign keys (the primary key fields from tblFamily and tblActivity). However, I think you'd need a family id field in tblClient with a value in each record whether or not the "family" is one person or more. I suspect you are listing each member in the same client table because you are treating each family member as a separate client. The fact that not all clients might reside at the same address, or have the same contact numbers, ages, etc. justifies a record for each member, even if that family member is a count of one.
I might have misunderstood some of what you have, as I'm not sure what you mean by child and parent. In Access terms, it refers to something like a many table vs a one table. You might mean actual parents and their children, so I'm not sure if you actually have a table for clients as well as one for those who are parents. Further complicating that understanding is the fact that you could have 2 members of the same family, neither of which are parents. Maybe post a pic of your table relationships if you have built them.
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