[nonameiguess]

This plus added stress, likely poor nutrition, missed exercise, a whole lot of things happening to new fathers that can lower measured serum testosterone. Whether or not it matters is an entirely different matter. Headline bloodwork numbers don't mean much out of context, and most of the outcomes you'd actually care about (athletic performance, muscle retention, general feeling of wellbeing and energy level) are all impacted by the same things whether or not testosterone is lowered. The one thing that might matter separately is sperm production, but if you care about being maximally able to get your wife pregnant again immediately after she gives birth, you can get that tested separately.