That's the SQL of a query. When you build queries through the graphical
query builder, Access is actually generating SQL for you. (You can see the
SQL associated with any query by opening the query in Design view, then
switching to the SQL view on the View menu)

To generate that SQL, create a new query and select your table. Drag in the
grid the Gender field, the Start and End date fields, and one other field
that you know is guaranteed not to contain Null values (the primary key is a
good choice). Change the query into a Totals query (there's a button with a
Sigma on it on the button bar, or check on the View menu). That'll add a new
row to the grid, entitled Total:, with a default value of Group By under
every field in the grid. Change that Group By to Count under the "other"
field, and to Where under the two date fields (You should also uncheck the
two date fields). Put <= #07/04/2007# as the criteria under the StartDate
field, and >= #07/04/2007# under the EndDate field. Run the query.

You can then use that query as the basis of a report if you want.

To have it prompt you for a date, put something like [Enter The Date]
instead of #07/04/2007# under the two fields. Note that dates must be input
in mm/dd/yyyy format.