Sure

https://avoiceformen.com/wp-content/uploads/2022/02/the-NOW-opposes-bill-to-give-fathers-shared-custody-2009.pdf

The documents in the PDF are just evidence of NOW's position and their opposition of presumption of 50/50 custody. I know the website can be off putting to someone like yourself. (no offense intended)

if you search Primary Caregiver in this link in NOW's website:

https://now.org/leaderdoc/addendum-now-issues-policy-manual-1997-july-2018/

You'll find this text

WHEREAS, because it is in the best interest of children to ensure their stability and continuity of care, there should be a rebuttable presumption that the primary caregiver of the children should be awarded custody;