Most pediatricians and doctors recommend against spanking:
https://www.sciencealert.com/the-vast-majority-of-us-doctors-are-now-against-spanking?utm_source=ScienceAlert+-+Daily+Email+Updates&utm_campaign=8f66aa77fc-MAILCHIMP_EMAIL_CAMPAIGN&utm_medium=email&utm_term=0_fe5632fb09-8f66aa77fc-365490661
The analysis by the APA:
http://www.apa.org/monitor/2012/04/spanking.aspx
Some research on the impact:
https://munews.missouri.edu/news-releases/2017/0731-spanking-can-be-detrimental-for-childrens-behavior-even-ten-years-later/
