Double Relationship With One Table in PHP

Let's say we have cities:

cities
id	name
1	city1
2	city2
3	city3

Let's say we have routes between cities, where each route has a starting city and an ending city:

routes
id	name	from_city_id	to_city_id
1	route1	1	2
2	route2	2	3

Suppose we want to get routes along with cities. The complexity here is that each route has two cities: start and end.

It turns out that the table with cities needs to be joined twice. With each join, the table will have to be renamed:

SELECT
	from_cities.name as from_city_name,
	to_cities.name as to_city_name
FROM
	routes
LEFT JOIN cities as from_cities
	ON from_cities.id=routes.from_city_id
LEFT JOIN cities as to_cities
	ON to_cities.id=routes.to_city_id

Suppose we have users. Each user has a father and a mother. Describe the storage structure.