Same appointment date for visitor visa

[pkt]

My mom and dad are planning to visit us in the US. Is it a good idea to get their appointment date/time as same date and time? My parents said that one of their friends told that if both mom and dad go together for visitor visa , they get rejected. I don't know the exact reason. But I would like to know if its better to book different dates for them.

Has anybody's parents experienced this kind of problem?
Another question is, they are visiting us because we are expecting a baby. so, is it a good idea to tell the visa officers that they are visiting because their daughter is expecting a baby and also to visit places?

Please let me know booking the same date , time for both my mom and dad is good or not.

Thanks!

[immihelp]

It is better that both apply together.

Purpose of tourist visa is "tourism", and nothing else.