Males are becoming less masculine:

In Western countries, testosterone in males has dropped by 30% since 1987.

https://www.forbes.com/sites/neilhowe/2017/10/02/youre-not-the-man-your-father-was/

https://www.healio.com/endocrinology/hormone-therapy/news/print/endocrine-today/%7Bac23497d-f1ed-4278-bbd2-92bb1e552e3a%7D/generational-decline-in-testosterone-levels-observed

Sperm count in Western men has dropped over 50% since 1973, possibly due to phthalates (plastic softeners), and/or due to sedentary lifestyle.

https://www.nytimes.com/2017/08/16/health/male-sperm-count-problem.html

According to a poll, Swedish men have become less masculine in the recent decades.

https://www.thelocal.se/20090429/19144

Females are becoming more feminine:

Menarche has receded from 16.5 years to 12.5 years since 1880.

https://www.ncbi.nlm.nih.gov/pubmed/15795887 (Fenner 2005)

Females who experience puberty earlier have a stronger preference for masculine faces.

https://journals.sagepub.com/doi/abs/10.1177/1474704916637876 (Batres 2016)

Females who experience puberty earlier have an earlier onset of anxiety disorders (i.e. higher neuroticism).

https://www.sciencedirect.com/science/article/pii/S0924933816300931 (Tondo 2017)

This might be affecting human sexual behavior:

Over 16 years (1999–2015), women’s orgasmic capacity has declined, from 56% of women experiencing orgasm in intercourse always or nearly always in 1999 to 46% in 2015.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5087699/

The primary factor determining orgasm frequency in women is their partners’ physical attractiveness and masculinity.

https://www.fpa.org.uk/sites/default/files/orgasms-in-women-an-online-survey.pdf

https://www.sciencedirect.com/science/article/pii/S0191886915001002

http://www.academia.edu/6514194/Mens_masculinity_and_attractiveness_predict_their_female_partners_reported_orgasm_frequency_and_timing

http://journals.sagepub.com/doi/full/10.1177/147470491401200507