Church teaching sees human sexual activity as an “occasion of sin” and has encoded and enforced what is deemed acceptable.
The “conjugal act” is not sinful as long as it is open to the miracle of new life. Any and every other heterosexual sexual act is “sinful” to some extent. 
All homosexual acts, though anthropologically  “natural,” have been decreed “inherently disordered” and “sinful” in any and all circumstances.
This “theology of human sexuality” allows all sinners to attend, but not to participate, in the Liturgy of the Word. Technically, they should leave after the Mass of the Catechumens.
The Liturgy of the Eucharist is a celebration that completely excludes certain sinners and tacitly admits others.
Church-going habits speak more of tendency rather than of attendance.
It is not just the young who look for a living, welcoming faith. It’s also the not-so-young and the in-betweens. It’s all of us.