According to the Ancient Chinese Gender Chart, if your wife is conceived in one of the following time periods in 2021, you have more chance to get a baby boy:
Jan 01 - Jan 12 (34 lunar years old, the 11th lunar month) Jan 13 - Feb 11 (34 lunar years old, the 12th lunar month) Feb 12 - Mar 12 (35 lunar years old, the 1st lunar month) Mar 13 - Apr 11 (35 lunar years old, the 2nd lunar month) May 12 - Jun 09 (35 lunar years old, the 4th lunar month) Sep 07 - Oct 05 (35 lunar years old, the 8th lunar month) Dec 04 - Dec 31 (35 lunar years old, the 11th lunar month)
Jan 01 - Jan 12 (34 lunar years old, the 11th lunar month)
Jan 13 - Feb 11 (34 lunar years old, the 12th lunar month)
Feb 12 - Mar 12 (35 lunar years old, the 1st lunar month)
Mar 13 - Apr 11 (35 lunar years old, the 2nd lunar month)
May 12 - Jun 09 (35 lunar years old, the 4th lunar month)
Sep 07 - Oct 05 (35 lunar years old, the 8th lunar month)
Dec 04 - Dec 31 (35 lunar years old, the 11th lunar month)