Is there a way of telling if the connector is male or female on a schematic?
Here's one general guideline.  It applies to connectors on the outside of the instruments.  If the connector supplies power or signal, it's usually a female (F).  This is done prevent shorting the signal (to something in the outside environment).  A female pin is harder to accidentally short than a male pin.  One can figure out from the schematic what's input and what's output.
A mnemonic for this rule is Source Side Socket (SSS).

I would deduce that DB-9 connectors on your schematic are F.  The common use of RS232 is for talking to PCs (directly or through USB-to-RS232 adapter).  Connector on the PC side is M.  Typically, the cable is F-to-M.  So, the connector on the other side is F.